Your roll problem could also be caused in part by adverse yaw. If your ailerons have equal throw up and down, the down aileron will have more drag than the up one which tends to pull the wing back with the up aileron wing moving forward. Looking at the plane from the top it would be a twisting motion, with the nose wanting to go left in a right turn, and vice versa. The effect is much the same as if you applied rudder in that direction, which is opposite of the way you want to roll. Coordinated rudder, in the same direction as your ailerons can overcome this and help perform a much better roll. The rudder corrects the yaw the down aileron is trying to cause. It often helps to have differential on the ailerons, with more up movement than down... sometimes twice as much is needed, depending on the wing used. I realize this may not be your problem, but I've seen it lots of times. Good luck!