Lanceair

I used a saito 100, 6v battery way up in that front compartment and balanced good with pull-pull rudder. I don't know what your engine weighs, but it sounds like you might be tail heavy without adding weight if you put your servo in back. Mine is still balanced for test flights
but I don't think I'll be moving it too far back. I think you should avoid starting out even a bit tail heavy and also avoid having to add weight with that (normal) size engine. Keep it light and it should fly great with the engine you have. Stay in touch. Randy