I have shot a lot of stuff with 16ga over the years. I haven't used a 12 in the field since the late 90's and I go bird hunting more than most people do. The best loads I ever used were Federal Classic Field loads from the early 90's with 1oz of hard shot at lower velocity. I bought two cases from a Walmart clearance sale at 2 bucks a box. No question that the purple hulls made them even better.
If there is a problem with 1oz loads in the 16 is not that they're 1oz. It's that they have cheap shot in them. I typically buy 1oz loads a case at a time, and keep a stack on hand just in case.
Couldn’t say it better. If I can get it, it would be 1 ounce of good shot at around 1200-1250FPS. The manufacturers usually give us what we think we need, so 1300+ isn’t uncommon, even if isn’t the best option. 5’s preferred for Pheasants. If a new shotgun, I may pattern for POI, or most likely will shoot some clays. If it is crushing going away clays from a gun down mount, it is ready to go hunting. Once POI is good, I’ll take any good shell and misses are on me.
Patterns on paper are for POI. With good shells I’ve never seen one that looked bad enough to think it would matter. And if the fit is close, POI changes insignificantly with different shells.
For the uplands, after seeing what 3/4 in a 28 will do, 1 ounce in a 12 world be fine also. Success mostly rests on how well you point or place shot, rather than how much you throw out.
If one uses it, TSS shot had changed the game on shot size, FPS and how much you need.