Ive about got my sky raider mach 1 completed i checked the center of gravity tonight and its really light in the rearend i kept adding weight until i put 122 grams on the back before it leveled out seems like this is alot is this common to have to add this much weight and is it ok to put it on the bottom side of the fuselodge?Also when i measured the distance from the wing tip to the edge of the rear wing or the tail fin it was just a little shorter (1/2 inch) on one side will this make a difference or effect the flying?