diff --git a/init.lua b/init.lua
index d43d4ec..09c7ea7 100644
--- a/init.lua
+++ b/init.lua
@@ -12,7 +12,7 @@ local function notnil_or(d, v)
 end
 
 -- Water level, plus one to ensure we are above the sea.
-local water_level = tonumber(minetest.settings:get("water_level", "1") )+1
+local water_level = tonumber(minetest.settings:get("water_level", "0") )
 local radial_step = 16
 
 -- Setting with no namespace for interoperability
@@ -34,6 +34,7 @@ rspawn.gen_frequency = tonumber(minetest.settings:get("rspawn.gen_frequency") or
 rspawn.spawn_block = minetest.settings:get("rspawn.spawn_block")
     
 dofile(mpath.."/src/data.lua")
+dofile(mpath.."/src/invites.lua")
 dofile(mpath.."/src/commands.lua")
 dofile(mpath.."/src/forceload.lua")
 dofile(mpath.."/src/debugging.lua")
@@ -87,6 +88,7 @@ function rspawn:newspawn(pos, radius)
         if under.walkable
          and not over.walkable
          and not minetest.is_protected(anode, rspawn.adminname)
+         and not (under.groups and under.groups.leaves ) -- no spawning on treetops!
          and daylight_above(7, anode) then
             validnodes[#validnodes+1] = anode
         end
@@ -109,8 +111,7 @@ function rspawn:genpos()
     if rspawn.spawnanywhere then
         pos = {
             x = math.random(-30000,30000),
-            --y = math.random(water_level, water_level+20),
-            y = water_level, -- always at waterlevel
+            y = water_level, -- always start at waterlevel
             z = math.random(-30000,30000),
         }
     end
@@ -118,7 +119,7 @@ function rspawn:genpos()
     return pos
 end
 
-local function confirm_new_spawn(name, newpos)
+function rspawn:set_player_spawn(name, newpos)
     local spos = minetest.pos_to_string(newpos)
 
     rspawn.debug("Saving spawn for "..name, spos)
@@ -140,21 +141,18 @@ function rspawn:set_newplayer_spawn(player)
         local newpos = rspawn:get_next_spawn()
 
         if newpos then
-            confirm_new_spawn(playername, newpos)
+            rspawn:set_player_spawn(playername, newpos)
 
         else
-            if rspawn.adminname ~= "singleplayer" or playername ~= rspawn.adminname then
-                minetest.chat_send_player(playername, "Please wait until a spawn point is available ...")
-                minetest.after(15, function()
-                    rspawn:set_newplayer_spawn(player)
-                end)
-            elseif rspawn.kick_on_fail then
+            -- We did not get a new position
+            
+            if rspawn.kick_on_fail then
                 minetest.kick_player(playername, "No personalized spawn points available - please try again later.")
 
             else
                 minetest.chat_send_player(playername, "Could not get custom spawn! Retrying in "..rspawn.gen_frequency.." seconds")
 
-                minetest.after(gen_frequency, function()
+                minetest.after(rspawn.gen_frequency+2, function()
                     rspawn:set_newplayer_spawn(player)
                 end)
             end
@@ -168,7 +166,7 @@ function rspawn:renew_player_spawn(playername)
     local newpos = rspawn:get_next_spawn()
 
     if newpos then
-        confirm_new_spawn(playername, newpos)
+        rspawn:set_player_spawn(playername, newpos)
 
     else
         minetest.chat_send_player(playername, "Could not get custom spawn!")
diff --git a/src/commands.lua b/src/commands.lua
index ebd7457..2080189 100644
--- a/src/commands.lua
+++ b/src/commands.lua
@@ -19,7 +19,7 @@ local function splitstring(sdata, sep)
         
         if idx then
             tdata[#tdata+1] = sdata:sub(1,idx-1)
-            sdata = sdata:sub(idx+1, idx:len() )
+            sdata = sdata:sub(idx+1, sdata:len() )
 
         else -- last element
             tdata[#tdata+1] = sdata
@@ -33,8 +33,8 @@ end
 -- Commands
 
 minetest.register_chatcommand("spawn", {
-	description = "Teleport to spawn position.",
-	params = "[ invite <player> | accept | decline ]",
+	description = "Teleport to spawn position, or manage invitations. See you current invitation with '/spawn invite'",
+	params = "[ invite [<player>] | accept | decline ]",
 	privs = "spawn",
 	func = function(name, args)
 		local target = rspawn.playerspawns[name]
@@ -43,23 +43,35 @@ minetest.register_chatcommand("spawn", {
         if #args == 0 then
             if target then
                 minetest.get_player_by_name(name):setpos(target)
+                return
+
             else
                 minetest.chat_send_player(name, "You have no spawn position!")
+                return
             end
 
         elseif args[1] == "accept" then
-            accept_invitation(name) -- TODO, only one at a time, must be accepted or declined
+            rspawn.invites:accept(name)
+                -- TODO, only one at a time, must be accepted or declined, and DO move player - not to be used lightly
+            return
 
         elseif args[1] == "decline" then
-            decline_invitation(name) -- TODO, free up invitation slot
+            rspawn.invites:decline(name) -- TODO, free up invitation slot
+            return
 
-        elseif#args == 2 and  args[1] == "invite" then
-            invite_player_fromto(name, args[2]) -- TODO, and DO move player - not to be used lightly
-        
-        else
-            minetest.chat_send_player(name, "Please check '/help spawn'")
+        elseif args[1] == "invite" then
+            if #args == 2 then
+                rspawn.invites:invite_player_fromto(name, args[2]) -- TODO
+                return
+
+            elseif #args == 1 then
+                rspawn.invites:show_invite_for(name) -- TODO
+                return
+            end
 
         end
+        
+        minetest.chat_send_player(name, "Please check '/help spawn'")
 	end
 })
 
diff --git a/src/forceload.lua b/src/forceload.lua
index 46bfe8a..41d507b 100644
--- a/src/forceload.lua
+++ b/src/forceload.lua
@@ -1,3 +1,6 @@
+local forceloading_happening = false
+
+
 local function forceload_operate(pos1, pos2, handler)
     local i,j,k
 
@@ -11,13 +14,22 @@ local function forceload_operate(pos1, pos2, handler)
 end
 
 function rspawn:forceload_blocks_in(pos1, pos2)
+    if forceloading_happening then
+        rspawn:debug("Forceload operation already underway - abort")
+        return false
+    end
+
     rspawn:debug("Forceloading blocks -----------¬", {pos1=minetest.pos_to_string(pos1),pos2=minetest.pos_to_string(pos2)})
+    forceloading_happening = true
     minetest.emerge_area(pos1, pos2)
     forceload_operate(pos1, pos2, minetest.forceload_block)
+
+    return true
 end
 
 function rspawn:forceload_free_blocks_in(pos1, pos2)
     rspawn:debug("Freeing forceloaded blocks ____/", {pos1=minetest.pos_to_string(pos1),pos2=minetest.pos_to_string(pos2)})
     forceload_operate(pos1, pos2, minetest.forceload_free_block)
+    forceloading_happening = false
 end
 
diff --git a/src/invites.lua b/src/invites.lua
new file mode 100644
index 0000000..3da515f
--- /dev/null
+++ b/src/invites.lua
@@ -0,0 +1,176 @@
+rspawn.invites = {}
+
+-- invitations[guest] = host
+rspawn.invitations = {}
+
+local invite_charge = {}
+
+levvy_name = minetest.settings:get("rspawn.levvy_name") or "default:cobble"
+levvy_qtty = minetest.settings:get("rspawn.levvy_qtty") or 99
+levvy_nicename = "cobblestone"
+
+if minetest.registered_nodes[levvy_name] then
+    levvy_nicename = minetest.registered_nodes[levvy_name].description
+else
+    minetest.debug("No such node "..levvy_name.." -- reverting to defaults.")
+    levvy_name = "default:cobble"
+    levvy_qtty = 99
+end
+
+local function get_players(p1name, p2name)
+    -- Check both players are online.
+    -- It is easier to implement agains online players than to manage offline interactions
+    local err, p1, p2
+    local errmsg_generic = " is not online."
+
+    if not p1name then
+        minetest.log("error", "Missing p1name")
+        return nil,nil,"Internal error."
+
+    elseif not p2name then
+        minetest.log("error", "Missing p2name")
+        return nil,nil,"Internal error."
+    end
+
+    p1 = minetest.get_player_by_name(p1name)
+    p2 = minetest.get_player_by_name(p2name)
+
+    if not p1 then err = p1name..errmsg_generic end
+    if not p2 then err = p2name..errmsg_generic end
+
+    return p1,p2,err
+end
+
+function rspawn.invites:invite_player_fromto(hostname, guestname)
+    local host,guest = get_players(hostname, guestname)
+
+    if err then
+        minetest.chat_send_player(hostname, err)
+        return
+    end
+
+    if not rspawn.invitations[guestname] then
+        rspawn.invitations[guestname] = hostname
+    else
+        minetest.chat_send_player(hostname, guestname.." already has a pending invitation, and cannot be invited.")
+        return
+    end
+
+    local hostspawn_s = minetest.pos_to_string(rspawn.playerspawns[hostname])
+
+    minetest.chat_send_player(guestname, hostname.." invited you to join their spawn point.\nIf you accept, your spawn point will be set to "..hostspawn_s.." and you will be taken there immediately.\n    This cannot be undone.\n\nRun '/spawn accept' to accept, '/spawn decline' to decline and clear the invite.")
+
+    minetest.chat_send_player(hostname,
+        "You have invited "..guestname.." to join your spawn.\nIf they accept, you will be charged \n\n    "..levvy_qtty.." "..levvy_nicename.." \n\nwhich will be taken from your inventory."
+    )
+end
+
+local function find_levvy(player)
+    -- return itemstack index, and stack itself, with qtty removed
+    -- or none if not found/not enough found
+    local i
+    local pname = player:get_player_name()
+    local player_inv = minetest.get_inventory({type='player', name = pname})
+    local total_count = 0
+
+    for i = 1,32 do
+        local itemstack = player_inv:get_stack('main', i)
+        local itemname = itemstack:get_name()
+        if itemname == levvy_name then
+            if itemstack:get_count() >= levvy_qtty then
+                return true
+            else
+                total_count = total_count + itemstack:get_count()
+
+                if total_count >= (levvy_qtty) then
+                    return true
+                end
+            end
+        end
+    end
+
+    minetest.chat_send_player(pname, "You do not have enough "..levvy_nicename.." to pay the spawn levvy for your invitaiton.")
+    return false
+end
+
+local function consume_levvy(player)
+    local i
+    local pname = player:get_player_name()
+    local player_inv = minetest.get_inventory({type='player', name = pname})
+    local total_count = 0
+
+    -- TODO combine find_levvy and consume_levvy so that we're
+    --    not scouring the inventory twice...
+    if find_levvy(player) then
+        for i = 1,32 do
+            local itemstack = player_inv:get_stack('main', i)
+            local itemname = itemstack:get_name()
+            if itemname == levvy_name then
+                if itemstack:get_count() >= levvy_qtty then
+                    itemstack:take_item(levvy_qtty)
+                    player_inv:set_stack('main', i, itemstack)
+                    return true
+                else
+                    total_count = total_count + itemstack:get_count()
+                    itemstack:clear()
+                    player_inv:set_stack('main', i, itemstack)
+
+                    if total_count >= (levvy_qtty) then
+                        return true
+                    end
+                end
+            end
+        end
+    end
+
+    return false
+end
+
+
+function rspawn.invites:accept(guestname)
+    local hostname = rspawn.invitations[guestname]
+
+    if not hostname then
+        minetest.chat_send_player(guestname, "No invitation to accept.")
+        return
+    end
+
+    local host,guest = get_players(hostname, guestname)
+
+    if err then
+        minetest.chat_send_player(guestname, err)
+        return
+    end
+
+    if consume_levvy(minetest.get_player_by_name(hostname) ) then -- Systematically notifies host if they don't have enough
+        local hostspawn = rspawn.playerspawns[hostname]
+        rspawn:set_player_spawn(guestname, hostspawn) -- sets new spawn position, saves, teleports player
+
+    else -- Host was notified, now notify guest
+        minetest.chat_send_player(guestname, hostname.." was unable to pay the levvy. Invitation could not be accepted.")
+    end
+end
+
+
+function rspawn.invites:decline(guestname)
+    local hostname = rspawn.invitations[guestname]
+
+    if hostname then
+        rspawn.invitations[guestname] = nil
+        -- Player not online, message simply ignored.
+        minetest.chat_send_player(guestname, "Declined invitation to join "..hostname.."'s spawn for now.")
+        minetest.chat_send_player(hostname, guestname.." declined to join your spawn point for now.")
+    else
+        minetest.chat_send_player(guestname, "No invitation to decline.")
+    end
+end
+
+function rspawn.invites:show_invite_for(guestname)
+    local hostname = rspawn.invitations[guestname]
+
+    if hostname then
+        minetest.chat_send_player(guestname, "You have been invited to join "..hostname.." at "..minetest.pos_to_string(rspawn.playerspawns[hostname]))
+    else
+        minetest.chat_send_player(guestname, "No pending invitation.")
+    end
+end
diff --git a/src/pregeneration.lua b/src/pregeneration.lua
index 687d62f..b6c4488 100644
--- a/src/pregeneration.lua
+++ b/src/pregeneration.lua
@@ -26,21 +26,23 @@ local function push_new_spawn()
     local random_pos = rspawn:genpos()
     local pos1,pos2 = rspawn:get_positions_for(random_pos, rspawn.search_radius)
 
-    rspawn:forceload_blocks_in(pos1, pos2)
+    if rspawn:forceload_blocks_in(pos1, pos2) then
+        minetest.after(rspawn.gen_frequency*0.8, function()
+            -- Let the forceload do its thing, then act
 
-    minetest.after(10, function()
-        -- Let the forceload do its thing, then act
+            local newpos = rspawn:newspawn(random_pos, rspawn.search_radius)
+            if newpos then
+                rspawn:debug("Generated "..minetest.pos_to_string(newpos))
+                set_pgen(len_pgen()+1, newpos )
+            else
+                rspawn:debug("Failed to generate new spawn point to push")
+            end
 
-        local newpos = rspawn:newspawn(random_pos, rspawn.search_radius)
-        if newpos then
-            rspawn:debug("Generated "..minetest.pos_to_string(newpos))
-            set_pgen(len_pgen()+1, newpos )
-        else
-            rspawn:debug("Failed to generate new spawn point to push")
-        end
-
-        rspawn:forceload_free_blocks_in(pos1, pos2)
-    end)
+            rspawn:forceload_free_blocks_in(pos1, pos2)
+        end)
+    else
+        rspawn:debug("Failed to push new spawn point - preexisting operation took precedence.")
+    end
 end
 
 minetest.register_globalstep(function(dtime)
@@ -63,8 +65,6 @@ function rspawn:get_next_spawn()
         nspawn = get_pgen(len_pgen() )
         rspawn:debug("Returning pregenerated spawn",nspawn)
         set_pgen(len_pgen(), nil)
-    else
-        push_new_spawn()
     end
 
     return nspawn