Sounds tail heavy to me. Does it require much or any down when inverted ???? If it takes no down or just the slightest touch, then I would say its tail heavy. Most planes, for flying the routines, like to be toward the forward CG limit, while they like to be towards or behind the aft CG for 3D flying.

The tail droping when you come off the power is also a good sign it is tail heavy.