RE: CONTROL HORN LOCATIONS FOR PULL-PULL SYSTEMS
I don't know if it's mentioned in those other links or not, but I've read oneadditional 'principles'. The distance between the two wires on the control horns has to be the same distance on the Servo horn. That way, when you turn the servo horn, you are turning a parallelogram.
The rudder servo should be on the centerline, naturally.
Bob