From what I see with caps I have, smallest to largest, #10 CCI, #11 CCI, #11 rem, #10 rem. I know, it makes no sense. This is just what I've seen. I currently have a few thousand caps in the above sizes, I know how they fit on different nipples. I find rem #10 to be the best fit for everything revolver except the 1851 Pietta made in '74, it likes CCI #11. I realize that from lot to lot etc, the caps vary. Also have some 1075 caps, just got those, haven't tried them yet. My 1858 will fire with pretty much any cap. Real strong main spring.(ASM, imported through CVA, 1990) The ROA, with ampco nips likes #10 rem. Those nipples are supposed to be for #11 CCI. My NAA .22 is also supposed to to take #11. CCI #11 will not fit. Causes the cylinder to bind. #10 rem fits and fires without a problem. Buy Treso nipples and see what works. YMMV. I haven't been doing this all that long. Ten years or so, others know much more than I.
My .02. Best luck.
NRA Life Member