Valve seat stones sizes?

Good info, thanks. I'm looking at a old Sioux setup. It is dated but looks pretty complete as far as the tooling, dresser, and pilots but I need to see it first. I figured I might need to purchase a couple of stones. I'm not doing it commercially so a $4000+ machine is out.
That is what my son uses Sioux . He has two of them and Dressers. The kwik-way are what is listed for sale new. Sioux are old school and hard to find. His works great.