fire ring diameters of various head gaskets

I get what youre saying/// but if I see that I'm into the fire ring with the gasket laying on top of the head what more am I gonna see by bolting the head to the block and looking at that? The bore size on the engine I am looking to use this head on is 20-over (3.420) the fire ring ID on the gasket I laid up there measures out 3.540 with a dial caliper. so Im already .120-over the size of the bore?
I have 2 more slant heads here that I set the same head gasket on, (untouched/unported) and the fire ring is right tight against the edge of the chamber on both of them. 1 "peanut" head taht is new enough for the AIR tube hole at the back of the head, and a drool tube head. I have since stripped the 2nd peanut head, and started carving on it. I'd like to use a peanut head because it leaves less chance for leaks... no drool tube seals to worry about.
Im thinking the original head "might" still be OK as I am hoping to shave it at least 0.060. I might go a bit more, as any head gasket that I use is gonna wind up at least 2x as thick as the original steel shim gasket. so to even stay "status quo" on original CR I am gonna have to shave the head at least 20-thou, so that means 20-thou more than I would have otherwise wanted to shave either it, the block, or both....
this other peanut head has never been apart but it already has a couple spots that look like my original head that I started with near about half of the valves.... but the head gasket I have "just" makes the ring around the combustion chamber w/o hanging over...... I would not have thought that a stock, untouched combustion chamber would already be bigger than an original, unbored cylinder bore..... I have not stripped the drool tube head, I might have to bolt that to the block and flip it over and see how the chamber lines up with the bore, once I get the block back......