RE: Roll axis trim changes with airspeed change.
I use aileron gyros on my F100 and P80 I do not think it will help. It only reacts to heavy movements like rough air. What you are experiencing is to slow. Heading hold might fix it but would be uncontrollable in the rest of the flight. It would be nice if you can find some one with the same plane that could loan you the wings for a test. What you are trying to cure is tough to find. Good luck Dan