Richard a plane when is upside down has a totally different flight envelope and characteristics . the weight distribution and momentum are totally on the different plane of reference. You arguments is to optimizing the CG for the worst case scenario and once the plane is right side up CG move to most stable position. I would agree with you if there was such a direct relationship. I know this is not the case with large heavy aircraft such as a commercial jet liners, if they go over , not even totally upside down ,they could never recover. I know you are speaking from years of experience, but why not set and optimize the CG for the normal flying condition. after all we aways trim our plane for straight and level flight and the same should be true for setting the CG. Best regards