RE: I need help with a lateral balance problem.
I'm going to assume that your forth sentence is correct. The aileron trim you are putting in may be because your rudder or vertical stab is not in line. You must laterally balance it and then deal with whatever other problems show up. Balance it by adding weight to the light side, say the left wing tip. Now look for something wrong with the fuselage/vertical stab/rudder. Correct anything, neutralize all of the trims, and make a test flight. Is the engine thrust set correctly?