It will depend on if you want to line it or not. I would say that the total thickness should be around 10 oz. More than 12 oz and it gets too thick, IMHO. If you've got Stohlman's books you can do it with no problem. Just remember if you're using a thinker leather than what he is using, make your pattern a bit larger to compensate for the added thickness. I'll edit this and add that you can use thicker leather but it gets harder and harder to form it to your pistol. Don't forget to oil your pistol before you form the holster and dry it off/oil it again afterwards!
