Good guesses but no winner yet... the steering wheel can't be indexed because it's keyed, and the rudder can't be indexed on the connecting arm because where they mate is square, not round. I also tried sliding the cable a little farther back thru this thing (hoping my attachment works!) but then I realized that would give me more turns in one direction than the other, so that won't work either. I should also mention the wheel is about 90* off when still and 60-70* off when at speed.
Keep the ideas coming, please!