Just my experience and opinion here:
“....an 11lb .500. About the same calculated recoil as a.470....” same weight rifle? The .500 is a NOTICEABLE step up in recoil. Dont be fooled by “calculations” you need to try them for real.

I have shot many of the big calibers in double rifles (4bore was a T. Bland single shot); various .400’s, .450, .458, .470, .500, .577 (both 90-650grain and 100-750 grain), 12bore, 8bore, 4bore.
The 100-.577 will make a believer out of you even in a 14lb rifle.
And don’t scoff at how freakin heavy a 14lb rifle can get in 100°F heat by the end of the day. Even in the heyday the guys that wrote about that stuff talked about .577’s and .600’s being exhausting to carry.

9 1/2-10lb .400, 10-10 1/2lb 450 or 11lb .470 is a nice sweet spot, my 2¢ worth.

Just sayin,
- Mike