Hi FHH, I am using a OS46FX with CG at 3.25 inch. It would have been easier for me if it is nose heavy ! I don't think I assembled anything wrongly except that with the clamp-on type engine mount, I had to push the engine as far back as possible to get 1/2 inch between the spinner backplate and fuselage front. Will that be too much ? I definitely can't get any closer. I know that 1/4 inch is better but that's as near I can go..........
