I'd go for a 70-100oz servo on the rudder.

I am planning on 2 servos for the elevators. A 537 on EACH elevator would be good, or if you plan on only using 1 elevator servos--then go for a 70--100oz size.

I'd probably use a 70oz servo on each aileron too.

If you go with the gasser--I'd definetly lean towards the higher torque.

Here's my setup:

JR 4721 on the rudder--150oz at 6V
JR 9011 on each elevator--75oz at 6V
JR 4131 on the ailerons--110oz at 6V
Airtronics 94145 on the throttle (maybe a JR DS537)

Thats WAAAAY overkill--but it's all I got right now. I'll never crash the plane because a servo stripped or failed.[8D]

I suspect the demise of this plane will be an early expiration date--directly attributable to a bad case of dumb thumbs.[:-]