Ah, a kindred spirit. I just took the back off the gimbal & tacked 3 wires onto the feedback pot terminals [ I do hate the lead free solder - stupidest idea ever] & brought them through a slot filed in the bottom of the cover. 50k preset across the outside terminals, 470k from wiper to centre terminal of fb pot. It's only a tiny offset, but it makes all the difference. Just realize that it is almost entirely an integral term, and takes about 5 sec to settle in the final position. Mine is only about 3 deg from centre on the offset pot.