my UCD Flex is touchy too, but it balanced fine, added a heat sink to motor after the first one had a meltdown.
using Futaba 3110 servos, 1320 LiPo, ElecticFly 35 amp esc on stock motor
start out with low rate, once up high then switch to high rate.

it was my first aileron plane, I think its a little hard to learn on, but it teaches you to use both rudder and ailerons to make your turns.