I have read your post and agree with everything you said.
You like Taylors formula, well here is a little known formula you might like better. Game weight = impact energy x sectional density x bullet area x 25.
Let's look at an M16, at 100yds its energy is about 1010ft/lbs, SD = 0.161, area = 0.039. This gives 158lbs. IF
a quartering shot is made use 18 for a multiplier. IF
the game is dangerous the multiplier is 12.5. This means that for game of the hoofed variety the target should weigh between 114lbs and 158lbs. IF
a wolf saw you first and charged lets hope it doesn't weigh more than 79lbs
If you use this formula on a Reminton double derringer you get about 25 which is unlikely to stop a determined attacker unless you hit that 15%.
ps. Most of these formulas take for granted that you have the right bullet for the job in hand.