RE: Spacewalker or J3 Cub
My Seagull Spacewalker flies great with a Fox 45. It comes with 1 male and 1 female pilot figure, one for each cockpit. It is a dream to land; just floats in very nice and predictable. I also use all the provided hardware except for the clevises and engine mount. I use Dubro clevises with the metal pin and keeper and a Dave Brown mount. The surfaces on the supplied mount are not true and I don't like the clamping idea; I bolt the engine to the mount.
Spend extra time around the cowl and make sure you have lots of cooling air going in and COMING OUT! Make sure you can fill the tank without flooding the engine. Make sure you can adjust the high and low speed needle valves with the engine running. Any time you save around the cowl in the workshop, you will quadruple at the field!