My .58 Kodiak uncrossed with more powder, then crossed again with too much. I did not increase further to see if they would uncross again - THAT result would have been interesting.
Nominal size for a 12 is .730" = bore size unless it is oversized as many new ones are.

I used a .684" in my own 12, but today, I have .705" and .724" moulds, as well as access to a .715". That one casts 1 1/4oz. at 545gr. in pure lead.

I need to do more testing, myself.