Well, AFAIK I don't have any of the really useful field effect girls (Edelweiss, Toad Lilly, Chocolate Cosmos, etc.) so I just keep my 3 rainbows (BB, Anemone and Flowering Peach, all evolved) in my helper team so my allies get a nice power boost regardless XD
The other two units in the team are evolved, not in-game to check which ones but on MY screen Squad Power is around 90k. FL is full though, do u ever get more than 30 friends allowed?