If you have an electric trim motor, set its position to mid travel using a 12 volt supply. You can confirm its mid position by measuring the resistance of the position wire pair or your indicator if installed. Then set the trim tab to the neutral position and play with the linkage length until the trim tab control horn and rod end hole line up. You will find that you use a very small amount of trim tab movement in flight and the indicated position means a lot less than what the stick is telling you.
Cam Andres
C-FTLL RV9A
Flying now and loving it.