Ditto to above. I have run 225s in all of my Q-500 aircraft for several years now, including the 428 planes (although for 428 I prefer the metal gear version). They work very well. One on each tail surface, one for the ailerons. Pleanty of power for the applications. I usually use a HS-81/85 mini servo for throttle.

The only real need for these smaller servos is to minimize size/weight for racing, to hit that 3.5 lb mark. For sport flying, that plane will fly just fine anywhere up to 4 lbs.

HiTec has a digital servo that is the same case size now too. Cost a bit more, but so far I have been thrilled with them... excellent centering. JR and Futaba also have digital "mid-size" servos as well for the same application.

If you are just flying for sport, and using a sport 40 or 46 engine, you can use good ole standard type servos. Just takes a bit of planning to install them properly.