I'd go with the long booms on the Sneaker. I had one with a ST .35C on a real pacifier, and liked the way it flew with the short booms, but with a heavier engine, the long booms would be da bomb. It wasn't a real fast design, tho mine was clocked at 116 two flights in a row (50% nitro) by guys that knew how. It'd do about 108 on M.Mist and propped for combat, but without the streamer. I had faster, and they weren't smaller. The wing itself is just not real clean, IMO.
Might add, that I have an original Flite Line kit of a Sneaker Mk. 11 (?) that has the long booms, and a sticker on the box that announces that detail.
Steve