If you go with Glacier Guides in Alaska, who had a notable string of #1 record book animals year to year, then the answer was, "as big as you can handle.... 375HH minimum."

Personally, my personal minimum would be a 375HH, in practice I would use a 416, as I am not interested in minimums or "just getting by."

Of course, the ultimate "fall back" answer is "whatever the legal minimum is" should bethe acceptable minimum, then again those folks (state game and fish) are in the business of selling licenses and the lower the minimum, the more potential applicants.

BTW, as a side note, I don't care if the rifleman is competent or not, start down that slippery slope and pretty soon you'll have someone claiming to possess the high end of excellence and justify hunting them with a 22LR or 223 or spear --- an easy conversation when one is 3,000 or more miles away and sitting at the fireside computer.

Good luck with your theoretical exercise.