RE: E-Pattern RX battery
I use 700 mAh E-tec, Jaccio 5,7V regulator.
I typically put back 35-45 mAh per flight.
5 digital JR servos.
It is probably possible to use an even smaller pack (e.g. 450 mAh) but I think that the weight reduction would be insignificant. (about 12 grams.)
Magne