I'm working on the 81" version and have already came to the opinion that the horizontal stab will have to be removable for transportation.

I'm not into it yet but I am surprised you are having problems with the elevator and rudder linkage. I could be wrong about the smaller bird but the big one uses (2) 60 degree bellcranks for each elevator control. That should elliminate any control binding. My rudder will be direct pushrod control from servo. Of course, the big OV-10 uses separate servos for each rudder and 2 servos for the elevater, 1 from each nacelle. A total of 12 servos are needed. (2) Airlon, (2) Flaps, (2) Rudder, (2) Throttle, (2) Elevator, (1) Nose Gear Steering, (1) Retract (I'm leaning toward fixed landing gear instead of retracts)