In my experience, insane power saves your plane from crashes. Maybe that's because I'm not that good yet, but being able to rocket out of a descending over if I get in trouble is very comforting to me. "Hovering at half throttle" is not the whole story. Everyone's plane "hovers at half throttle" it seems, but the vertical pull-out is vastly different from engine to engine. I think that the weight increase with a larger 4-stroke is negligible on a plane like this. I don't have a UCD, but I have 2 other .40 sized 3D planes with similar weights and wing areas.

If you want the power and the extra weight bothers you, try switching to a lipo setup (you get 6 volts that way too instead of 4.8), and voila, there's your extra weight back off, plus you've now got more torque on your servos. Hehe, this all assumes of course that money is not a factor. A Saito 100 costs a great deal more than a typical .46 2-stroke. Not to mention the cost of lipos and lipo chargers.