My ref was the Briley website chart.

But back to thinwall chokes; I'd give a lot of consideration to those comments about not screw-choking this gun. In todays market, this seems to be a big detractor to buyers. However, as always, it's your gun and your choice. But nevertheless, if you use it as is or even open the chokes to your best guess for your uses, you can always have it screw-choked later. Why leap to a point if you can simply stroll there?