If you plug the two aileron servos to a y-harness and then into channel 1 on your receiver, they will move the the correct way in
relation to one another for ailerons. Just make sure that they are moving the "Right Way" Do a bench test with them and you'll see. I have a Sig 1/4 scale clipped wing Cub that I fly with one elevator servo,(70 oz ) Have never had any problems. I have flown a 1/4 scale full wing Cub and it does not like to turn on ailerons alone. As one of the guys stated eariler Cubs turn better when you add rudder. I would not mix the aileron and rudder at least until you have test flown the plane and are comfortable with it. then you could experiment with mix if you like. To me, using rudder and aileron independently on this bird will get you used to using the rudder in the air. But thats only my opinion. I put my first big wing cub in on the first flight because I didn't know about the rudder thing. I got help and was glad I did. Good luck Impalas