Nice points, Ed. You have obviously thought this out a lot. Good going.
One day, in 1964, I was hunting pheasants in Cheju Do Korea. I had my old Iver Johnson 20 ga single, the one I grew up with. It still kicks like a bay steer. I'd gotten my 16 birds, like others, and the hunt was done. A fellow handed me his Sauer (I likely misspelled the name?) 20 side by side. His gun happened to fit me like a glove, I didn't have to hunker around into it, like my gun. What a surprise! I'd pop it to my shoulder as a bird flitted by, and it was automatically lined up on whatever I was looking at. WOW!
So, were I to buy a gun today, the first thing I'd do is trot us right over to a stock smith and get it fitted. Then, I'd start learning your points as per your article.
BTW, I see you like long barreled buns. Come on up, and I'll let you shoot my LeFevre 12 ga single, 32" FULL (as in really full) choke. raised rib, 9 1/2 pounds. It guts birds at 25 yards.