Koko ..did I read that right that you needed to add 17 oz? 1lb 1oz to the tail? I was tail heavy as it was ..I had to add 1.25 oz to the fire wall but thats with the cowl off and the cowl weighs one once...yadda yadda...in the tail I used servos that weighed 1.8 oz each if i had of went with lighter servos I would'nt have gotten the speed I wanted ....try moving your battery pack up right behind the canopy maybe? just shoting soem ideas from the hip ...
John