Great!
I just figured the math out... took a little bit to get the gears on my head going. But you are right, it is very simple
A couple of Y=mX+b, then just find the intersection of both curves by making one equal to the other, and that point becomes 0,0. now basic trigonometry on one of the curves to get the angle of rotation and thats it.
Brian, can the plugin be made so that you can add a compensation if you are using a touchplate on the side of the piece?
Again let me know if i can help.
Regards
Fernando