I think my personal recoil limit is probably the .375 H&H magnum in a Win 70 Alaskan. The Model 70 Safari is heavier and more pleasant to shoot. All standing. Not sure about the bench, although I think I tanked a few hits to get the 2.5x20mm sighted in on the Safari.
Had a Ruger RSM in .458 Lott/WM and after four 500 grain rounds (standing) with a PAST pad on, I remember thinking, "Maybe this is a bridge too far...".

I had a flinch for a few weeks after that. The .375 H&H didn't give me a flinch and I shot that quite a bit before. Neither did 12 gauges at skeet and trap.
Still like the notion of a .458 WM: I think it's a sensible answer to the Marlin .45-70. The 325 grain Leverevolutions were pleasant to shoot in the Marlin. Drive the same weight in a copper solid .458 WM and I bet it would be outstanding for far bigger stuff, while still pleasant to shoot. I also think a 450 grain A-Frame would give up nothing to a 500 grain bullet, and allow for uncompressed loads. I suspect it might be a better standard than the 500 grain bullet now, given improvements in powders and bullet construction over the past 50 years.
However, reading about retinal detachment makes me question my interest in the .458 WM even more. And if I'm just going to load 325-350 grains for lighter recoil, then I might as well use the .375 H&H and get more SD out of similar bullet weights.
I find it curious that Winchester offers their "Alaskan" model in a traditional wood stock and blued barrel configuration.
Wasn't their previous Alaskan a stainless laminate model?
FN/BACO had a run of SHOT show stainless laminate South Carolina Alaskans in .30-06, .338 WM, and .375 H&H. I think those should have been the standard Alaskans and not the blue/walnut ones. Maybe FN will come to their senses.