Bruce — Clearly, aside possibly from Doc Ashby himself, we can’t be of much help in directly answering your question, I suspect because such direct comparison doesn’t exist. To try and compare all the possible variations would expand geometrically to quickly become impossible. However you might learn what you need to know buy reading Ashby’s latest study updated, posted here in the Ashby Forum. Basically, the gains in penetration increase by a greater percentage in lighter bows as FOC goes up, than in heavy bows. I think that may be as precise as we’ll get without specific setup-to-setup arrow setups. To restate the bottom line in all of this: Ashby’s research demonstrates that the “minimal heavy bone penetration” weight is 650 grains if you’re looking to have a foolproof setup. That comes first. Beyond 650 total grains the more of it up front, that is the higher the FoC, the better the penetration. Perhaps another member here can clarify my muddy attempts to help. Best luck, dave