J-3 Cub build

[TOTAL CARNAGE]

Hello all. Dan here. I have been flying for 30yrs and have had a few electric rtf's
but this is my first kit built glow conversion.
It's a Great Planes 20. J-3 Cub with a 61" wing.
First, I built the wing with a servo for each aileron (strip ailerons) so I could set
differential. Now, the question.....Do you think flaperons would be of any use on a plane like this ?
second, I am a bit over powered with a GH2820-05 spinning a 11-6 prop, a GH 50a. esc and 7a. ubec. I would like to use a 3s lipo. Any idea what size I should get ? I would like to get about a 10min flight and figure this motor will only need half throttle to cruise and should go vertical at 3/4! A least that's what my math said.......amps watts = kw's - volts...???... I like electric but can't get the hang of figuring the math out.