Eeeh, still awfully monocolored. Groot's best move is the blue, but you need all the blues you can get for FT. HB is a better boosted char to use, since his blue sucks. And then some yellow/purple guy for coverage...kingpin?
I just go straight for yellow for Iron Man. He generates Blue, Green and Red. Let Groot use the Green, then stun with Blue with Thor, then unleash red. Go back to collecting yellow and repeat. Super powerful