I've been reading up on the use of Ackerman (geometry) in pull-pull systems. To make a long and complex story short, it seem that what it needed is to have the connection point on the horns be just slightly behind the pivot point.

Well, it's too late for that on my rudder; the control horn is perfectly centered as I thought it was supposed to be. The question is, can I still work some Ackerman into the system by altering the setup up of a bell-crank at the other end -- the servo end of things?