I flew my 105" Sig 1/4-scale Cub with a Saito 91 for an entire season, and had a ball with it. Plenty enough power for scale-like flying. When the front bearing finally gave out, I moved my Magnum 1.20 four-stroke into the Cub. It now has plenty of reserve thrust for climbing out aggressively. I spend most of the time flying with the throttle cracked open somewhere past idle. Cubs should be flown on the wing, not on the engine, and the Magnum does a great job of putt-putting all day long at partial power. My 20oz tank lasts a long time at these power settings.

BTW, true Cub fans know about the Cub Nuts event next month in Oregon. Come and be part of the "yellow swarm"!
http://www.cubnuts.com/