Ed, thanks for this valuable background information. It's as interesting for me as several others before. Somewhat reliving my youth when I couldn't afford it, I built the Kwik-Fli in a simulator. There I can duplicate your statements and also the usual setup values given on plans.
Scott, you have a very nice model, with the original paint scheme even enhanced. Considering the nose landing gear and the canopy, it must be a Graupner version so it should be at least early 70s.
As to the control throws: There are recommendations for the ailerons. The RC MODELER article says: Total aileron deflection is only about 5/8". The German plan version says about 16 mm, what's just the same and converts to about 11 degrees. I'd recommend to set 11 degrees up and 10% differential.
Rudder deflection is limited to 30 degrees by the elevator cutout, and I'd set both rudder and elevator to 30 degrees. You'll need all rudder effect you can get (after all the Mark III had that bigger rudder), and 30 degrees elevator won't cause a stall inadvertently, but you'd even need it for spinning and snapping.
Of course a more back c/g helps also. The plans show it exactly 4" behind the leading edge, what gives a rather big 13.5% static margin (proving Ed's remark). By the way, that matches the decent decalage recommended in the plan. RCM says wing leading edge 3/32" higher than trailing edge, the German plan says 1.5 to 2 mm. That converts to 0.3 to 0.4 or even 0.5 degrees incidence/decalage.
Under today's circumstances (see Ed's remark), I'd set the c/g to even 5 1/8" (well, carefully in steps) giving a more pleasant 3.5% static margin. The model will barely stand on it's main wheels (what was recommended in this forum for other pattern models). Incidence/decalage should be reduced to 0.1 to 0.2 degrees to make the model pretty neutrally stable both upright and inverted. With the stock trim it's stable only upright and needs substantial elevator inverted.
Maybe you'd have to somewhat close the throttle of your powerful engine to notice that.
