Good thing about trimming the aileron settings on the UglyStick is the wing is symmetrical. With most symmetrical wings, it's fairly easy to eyeball the straightback position that usually works best for them.

First priority is to see that the wing isn't warped. Then that the two ailerons are straight and both have the same deflection. Then try to see that they look to be straight back, not up or down. Then fly and sort them from how the airplane handles. They usually are almost invisible from then on with the average sport airplane being flown by the average flyer doing what he wants to do.