Basically it is then the same as in "normal go for 250/200" games. The ranking is according to the planet numbers. Only the mutiplier to the achievement is modified where and which one you have been in an alliance. So I think if e.g. Player 1: 100 planets, Player 2: 90 planets, Player 3: 80 planets, ... is the distribution at t100 then - if player 1 and 3 are allied - player 2 is second but gets less achievement than player 3 (multiplier 2).
Show Media Item - Basically it is then the same as in "normal go for 250/200"...