Well I exchanged my 1500mah battery for the standard 600mah battery from futaba in the same fuse position. That changed my CG from 90 to 80. Thats 20 off from the orginal booklet setting of 100mm. However, at 90mm CG on a straight pass at 3/4 to full throttle this plane just wants to climb up. I've been using down elevator to keep it more level flight. The two batteries are about 1.3oz in weight difference. Will see what happens on the next flight. The bigger battery will keep it also at 80mm CG if i move it forward on the fuse and just behind the servos.