RE: rudder requirements
You NEED 4.5". This sounds odd, but it is because of the thickness of the tail section.
With a 4" bellcrank and a 4" spread at the control horn on the rudder, the control horn will hit the fuse at large deflections.
The 4.5" bellcrank and the resultant 4.5" spread at the tail prevents this.
I used SWB 4.5" offset self-adjusting setup with cables crossed, 2 x 5955s for power, and it works like a champ... plenty of rudder power. Of course, I haven't had time to fly it for 6 months now. Work and this damned heli habit are gettnig in the way.