I've been experimenting with a NextStar using full span flapperons with very good success. One thing I've noticed is dropping the ailerons about 1/8" or so makes a big difference in the way the plane flies - and it even seems to have better stall characteristics. You may want to think about trying that before you cut into the ailerons to make seperate flaps. At 7500 ft. you'll need a fair amount of aileron throw on the plane. Dropping the ailerons a bit still leaves them intact so you'll have the maximum amount of power from them. Even better if you have a radio that can operate flapperons - you (or your instructor) can find the setting that best works for your conditions.

Hogflyer