Custom aerobatic planes that are set up for 3-D will have a aft CG. To my amazement that can be quite a lot of difference setup. One option that I have done is to move weight. Don't add weight just move it (tank, servos, batteries, Rx, and engine). Buy your self and good CG balancer so that you can move things around to get the best setup. A General rule for weight is 1/3 aft 2/3 forward. In your case.....that would mean 32 oz. needs to come off the back of the plane.

Good luck,

Tim