Bloodmap Triggers

Ok, i'm making a bloodmap and i've got the map and units set out, and all the other triggers, but one eludes me.
I want the units to spawn from the circle ONLY if the player has less than 36 food (each unit takes up one food) AND, ONLY if there are NO units on the circle (i've set up a movement trigger so the units move to a location near the front. What conditions do i need to do this? And how can i set it up so whenever any unit dies, the owner of killing unit gets 1 lumber?

Thanks for any help you can give me.

I belive under a interger comparasion there is a "food used". Try looking for that. The problem with counting units in region by a player is: it will count the dead ones also.

As far as the 1 lumber per kill:

Events:
A Unit by Playter 1 dies
A Unit by Playter 2 dies
A Unit by Playter 3 dies
and so on

Conditions:
None unless you need 1

Actions:
Player Property - set player lumber = to curent lumber + 1

Thanks muchly :D but the reason i dont use the counting units in a region is because it will count the dead ones, hence why i need the food used trigger. I'll tell you if it worked asap.

Well the condition works, now it doesnt go past 32 food, but i still have a propblem, how do i make the trigger repeat so that untill 32 food is met, the units keep spawning?

Well since i cant edit my posts for some reason, dont bother with the one above, read this instead:

O.K. i've got it so the units spawn, but i have a slight problem.

Whenever i move the unit onto the circle, it creates all 32 units instantly, how can i make it so that it waits half a second or so to spawn the next one?

Also, once the 32 food has been met, instead of it continuing (a unit dies and then another respawns to replace it, nothing happens, unless the unit in the "Spawn Area" moves off the spawner and back on.

If you dont understand here is a quick map.

_______
| |
|o |
¯¯¯¯¯¯¯

_______
|o |
| O |
| |
| |
¯¯| |¯¯
| |
| || |
\/
To Battle

KEY:
o - Is the spawn circle
O - Is the spawn tower

Now, in the top bit (the spawn area) 1 of each unit you can get is spawned, when that unit is put on the circle in the Spawn Area i want the 32 units to spawn, with short half second or so intervils between spawns, in the circle on the main island, when the spawn tower is killed, all units owned by the player die and the unit spawning stops.

Now i got it all working except the spaceing out bit, how can i make it space out?