My Venus was requiring quite a bit of down elevator to fly inverted even though the CG was aft around 7.25". Coupled with the necessary up elevator trim to maintain a positive angle of attack to fly it took about a third stick travel to maintain level inverted flight also making point rolls more difficult to perform well. The solution we found was to add another half degree of down thrust to the engine setting it right at two degrees improved things significantly. I had tried adding shims under trailing edge of the wing, but that didn't workout that well, the airplane would trim half throttle then want to climb significantly when power was applied with the extra incidence.