So here is my take at this mission:
I went leather only, because when you go iron on this mission you get attacked faster(i think, might be wrong though).
a big problem on this map, is that there are no starting trees, so it takes a while to get started. to fix this, i build some woodcutters near my ally and stole some of his wood.
after getting 6 farms up, i build some towers near the green enemy, and finished my leather production. i build up an army and lured the green enemy in my towers.
after that i could just walk in green his base and the mission got a lot easier with only black remaining.
to defeat black i just build up an army again, and build some towers near my stone so i could just lure black in the towers and kill his entire army there.
it still took me 2 hours, which is the longest time i needed to beat any mission in tsk (not counting mission 20) with building a full base.
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