I have the same servos and a Wren 120 in mine. On an engine test run I noticed the elevator shaking on full throttle, so I did shim the engine front end a bit to direct the jet down and away from the elevator. C of G is as it should be, and I need a bit up elevator to fly level. The servos are carefully installed so that the maximum movement is the maximum elevator throw. So far these servos seem strong enough, when using the whole movement. I may shift the CG still a bit more aft.

TP.