Geoff,
To be honest, you really do not need anything fancy. It really depends on the results you are looking to achieve. There are guys keeping it fairly simple and cost effective by using the stock hardware and good standard ball bearing servos on all the control surfaces except the rudder which would require a higher torque servo for optimum knife-edge performance.
The next level would be to go with higher torque coreless ball-bearing servos on all control surfaces and a higher torque on the Rudder. This will provide for much better centering, smoother transition through the movements, and depending on the servo, faster speed. If you ahve been flying for a while you can feel the difference in this upgrade.
The extreme would be to install digital servos on all control surfaces. Flying giant scale planes, I have a lot of digital servos. Digitals provide the best performance in my opinion. They have the best holding power, centering, but most importantly, linier movement. They are well worth the money....... if a higher budget for this project can be determined, "worthwhile".
I hope this anwers your questions. If you need more specific specifications for the servos, let me know.
www.ultra-rc.com [email protected]
Ultra-RC
Brian Hughes
250 Old Marlton Pike
Medford, NJ 08055
609-714-0040