G-38 would be perfect choice power wise, mine was powered with a Quadra 35 and it was just right, balanced right on the nose. The only drawback you'll have with the Zenoah is that the spark plug wire will be visible, not so on the Quadra. This is probably one of the best kits ever built by anyone, fantastic flyer, will do any manuever on the book in the most scale like fashion, and because of this, you "must" replace the aluminum strut holding fittings that come out of the fuselage with brass stock material of same thickness, I would also change all the metal fittings that are used by the struts for brass. I liked to do snaps, lomcevacks and spins with mine and although I always performed a thorough pre flight check up (including the strut attachments), lost mine soon after take off while flying straight and level. It was rebuilt and finished up the same way and flew it for over 7 years when a **** turned his transmiter on without checking the impound box while I was doing a fly by, it went straight in and was totalled.
Only vise on this airplane is that if when coming in for landing and it nears a stall, the elevator looses effectiveness abruptly, and this is before it stalls, so carry some air speed until touch down, other than that, it is a sweet flyer. By the way, at least I was able to get a new kit for my loss and I have it ageing in my hangar.