I'm running a SIG Something Extra with an O.S. 50 SX and I'm contemplating how to move the battery pack behind the fuselage for CG purposes. It's either move the pack or add weight to the rear. Keep in mind that this is to put the CG at beginner-based spot according to the instructions. For maneuverability, I would even have to go farther back. I've already installed the servos and would rather not take them back out, so would it be such a terrible idea to cut a rectangular hole in the rear fuselage, insert the battery then repair. Even if I do decide to remove the servos for underneath clearance, I can't reach under the servo tray enough to get to the back of the fuselage to mount the battery. Any ideas? Also, the plane hasn't been off the ground yet and this is my first non-trainer - any suggestions as to what to expect, etc. would be really cool. Thanks