So, thank you everyone for the continued advice.
It might not be clear that this tear down is from from compression loss after 200 perfect run hours or so, almost certainly due to carbon build up. I believe my 'squish' at TDC is already good. I did check it, and while I to improvise, it's close to .025"
Once I got the cylinder on - no head, no bolts - , just turning it over I can hear the body 'breathing' a ton more than before. I think I'm good, and it was stuck ring(s).
I guess the question continues to be: should I *replace* the copper head gasket, or just reuse the one that was there?