The major snag here is not so much the aileron length as the wire torque rods. Using those torque rods - the wire lengths bent to stick into the ailerons and then upwards to give leverage points for the servo - is about the oldest way to move ailerons going. It dates back to when advanced radios had four channels and servos were big and expensive.
Quick way round. Lose the torque rods, keep the kit ailerons - they will do you fine, this is a well regarded and proven model. Use two servos, one per aileron. Use either 'standard' servos, or the likes of Hitec's HS225 mini servos. Mount those servos out near half span into a mounting based on wing ribs, run their leads, with extensions if needed, through paper tubes going through round holes you add to the ribs. At the centre, you can either join these leads with a Y connector or to two receiver channels for tranny mixed control.
I could show some pics of how to do this,but due to circumstances involving house painting, I can't get to my real computer and photo files right now. Loosely, there's two tidy, efficient ways to mount servos inside the wing profile or they can hang out under the wing with the servo arm and aileron horn moving at ninety degrees to each other.
Changing the aileron span and chord will require a fair amount of structural redesign around the wing TE and two servos would still be the easier way to waggle them.
Real cheap suggestion
. Do the research and figure out how you want to proceed before starting to build your model. It's much easier in the long run.
Good luck with your project