Voila! I reversed the c-clip cancelling cam 180* with open end facing the switch location on the right.
The left turn cancels with 1/4 turn of the steering wheel left and a bit over 1/2 to cancel the right. I suppose some fine tuning might get it better, but I can live with this. The other way required almost no left turn steering movement to cancel the turn.
What have we learned? Squarebird Forum has some bright guys! I'll bet there are cancelling cams set the other way that work. Thanks everyone!