Of the readily available calls, I'd start out with a David Halloran Twisted Sister. There are a lot of not so readily available calls that are outstanding. Platz, Corder, Roberts, Daybreak, Trice, Strawser, Schaeffer, Dawkins, Cornelius, Townsend, and the list goes on. I've got calls by all of them, and the pot I go to is a Lon Trice stoned aluminum in an acrylic pot