The classic CG test is to roll inverted in a 45 degree upline and release the controls. A slightly forward CG that will give you a smooth flying plane will pull slightly to the canopy. When I was setting up my Extra, a pretty experienced IMAC pilot told me to look for a 4-6 count before the plane was heading downwards. I followed that advice and got a very smooth flying plane. I could get better snaps and spins with a more rearward setup, but the plane does well enough. I do need a fair amount of mix for knife edge flight, but that's a small price to pay for a plane that doesn't get tossed around in the wind and is very predictable through all maneuvers.