I have used hitec hs55's, hs50's, and the latest was a cirrus 4.7gm servo (real tiny). The mains were both on one servo, and the nose was on a separate servo (two servos for 3 retracts). I have no exp with planes heavier than 1.5 lbs so can not comment on retracts to use. here is a thread which show the retracts install, go to about the 60th post

http://www.rcgroups.com/forums/showt...5&page=5&pp=15