For 3d work I don't think you can have too much servo on the rudder. I have a 1/4 scale Sukhoi that isn't that much larger than the G.P. Extra. I am getting blowback in knife-edge with a JR 8411. Wow. I used to have a 4721 on it and I could see the blowback with the naked eye. With the 8411 you can still see it with Binoculars or video playback. At the very least spring for a cheap Hitec digital at Servocity for $54.