RE: Which engine for 1/3 pup
Mine has a G62, and the Pup is a heavy one at 40lbs. No shortage of power, does every manoeuvre the full size did with ease. Never got the sense ever from it that it was lacking in power - all you have to do is calculate the wing loading on it (way less than 20oz. if I remember correctly), plus the super lift from the undercambered wings, and if there wasn't all the drag it would be a glider!
Cheers,
Mike