I think my team it's the opposite of yours.
Today I won the Cup final and that makes 36/37 successful finals.
But i don't think it's only luck.
Some day, if I 'll find the time, I 'll make a mini guide how to prepare for a final.
till then, I suggest you to play with 3Dw-2DMC-2MC-AML-AMR-ST
start with def/counters, the other neutral
and switch them later in the game.
Good luck