I seldom use this argument because I test everything for myself but just imagine how many times what you proposed has been tried already. I've witnessed it several times, myself and can't recall a single instance where heavy for caliber bullets won or even were close, in a Sr br match. It's been tried a lot, though. I am in about a 4cyear long test of trying to optimize twist, bc, velocity, accuracy and every aspect. I can say that a 6mm 12 twist seems to give up nothing to the slower 13.3-14s and I've won national level matches with both 68 and 80 class bullets. After that, things do get more sketchy. The mid weights are close but not quite there and the heavies have never been up to Sr br levels of being competitive,..regardless of twist. It's simply harder to make pure accuracy as the projectile gets longer. The last 4 years have been about finding that balance point..for lack of a better way to put it.
Times flies. It's been at least 5 years now.