The SE will 3D fine if you build it light and have enough power. Use light wheels like the Dubro featherlites. Use a micro servo for throttle. Keep the fuel tank as small as possible for whatever engine you use. I've known people to cut out one rib to save weight. Some of the ply formers can be subbed with balsa. All of this helps to keep it light.

You could use the green foam that is used for flower arrangements as your plug. I would seal it with something like artists gesso. You could try mold release, but dripping glow fuel would probably be easier as that eats the foam out fast.