Aside from the DME in the recipe, I like to mash my own high gravity beers (RIS, Barleywine, etc.) ~ 148 or 149F. Personal preference - with a normal strength beer some styles might finish a bit thinner than desired, but I've never found it to be the case in a high OG beer. But I have had big beers finish higher (and sweeter) than I wanted. Lots of different ways of getting there, though !