Here's what we're doing on our new 37% Yak Pull Pull Rudder, for what it's worth. We've studied the Ackerman principle, and studied the SWB diagrams. We're using a slightly modified "Example B" from SWB. We have an offset SWB Servo Arm which is about 4 1/4 inches across from cable to cable. It is offset 5/16 of an inch to the rear. On the rudder we have a Control Horn which measures 4 3/4 inches across from cable to cable. Cables will be crossed. The modifier will be: The control horn is offset to the rear about 1/8," per Mr. Ackerman, to help keep both cables under tension all the time. We made the control horn slightly longer than the servo horn so that we can observe the amount of rudder throw we will get, and then be able to "dial it in" by rotating the connectors on the ends inwards for more throw.