I had a 50 on it at first, then a Saito 72, now, I've got a 91 on it and love it. The throttle stick moved less from idle as the engine increased size and now it's mostly 1/3 throttle or under but when I want to go up in a hurry, it'll do it. I do a lot of low passes and fly around the field at a foot or lower many times. WHen I need to get some air in a hurry, I just blip the throttle and ta-da, theres another two feet of altitude. I like just idling around in the air so the 91 does fine. The engine wieghs about the same but has more power and I can really make use of the extra torque. I have a 15X8 prop on the 91 so it might be a little over-propped for a 91 but like I said, half throttle is really all I need. If I point it straight up, I can use 3/4 to full throttle.

The real beauty of this setup for me, is that to fly around, it just putters around the air and, I think, sounds MUCH more scale than screaming through the sky.