A 25 amp esc should be plenty. I use to have a u-can-do 3d ep, and a e-flite 370 inrunner 420kv. I had a 1/2 throttle hover and 3/4 unlimited vertical. I had a 6.6-1 gear ratio, and a 12x6 prop. It was a nice setup, but I think a good gearbox, not e-flite (they wear out too fast), would be good. As for the servos hs-55 are plenty of power. And for my motor setup, I was using a 10 amp esc and was working just fine.

LeBlanc