I agree with Mark, we should be using the shortest possible servo arms to get the best mechanical advantage and to increase the resolution of the control surface movement. The other option to moving the servos outboard is to move the control horn on the elevon, but I've just checked and it would need to move out over 1" to get some clearance between the pushrod and the fin. I think I'll move the serovos out 1/4-1/2" tonight.

I'm using carbon pushrods so I can't have them fould the fin (even if I wanted it to, which I don't).