bubbagates and Mike East and jon595 - ya'll have put "School in Session", and very patiently explained to me how to fix what I was SEEING, but not UNDERSTANDING. I have just "fixed" my BME Yak, and it is now WAY close enough on ALL three rates (yep, I fly using all three)....

I'll translate, so ya'll can tell me if I "got it".

Because of minor mechanical issues - hinge line to servo center, differences in parellel "height" of servo shaft to control takeoff, and differences in the control takeoff itself (even getting them the same distance away from, and OVER, the Hinge Line), the system introduces what I will label "radially-induced-rotational-differential".... Because the attach point is pivoting in an arc, and the control point takeoff is moving in an arc, we got troubles in the RELATIVE RATE OF MOVEMENT Have I got it so far?

So.... the long stick (or cf rods) to align the mechanical "neutrals", then tweaking the sub trim to change the REQUIRED LENGTH OF THE PUSHROD TO KEEP THE MECHANICAL CENTER, causes the need for "sub trim".

The sub trim changes, in combination with changing the length of the pushrod, maintains neutral "zero" mechanically, and corrects for the radially-induced-differential from the servo arm movement.

That's the ball game, right????? Game, set, MATCH. THANKS TO ALL OF YOU!!!!!!!!!!!!!