I built my Midstar with an OS46FX. I would recommend rotating the engine 90 degrees. These are a dirty plane even with an exhaust diverter. I left the wingtips, I cant really tell you if they serve an important purpose but I think they look good. I also went with the dual airelon servos as you are thinking of. Even as a tri gear with the 46 the plane came in around 5-5 1/2 lbs. Light plane once complete. It will fly great with the PRO46.