Good looking hunk of Cow! I would not worry about a smoke ring, it is just a visual thing and has nothing to to with flavor. If you want to get it put the brisket on the pit strait from the cold box. The smoke ring will stop forming when the meats surface temp reaches 140 deg F.
I never met a Cow that I didn't like with a little Salt & Pepper! Certified PORK-A-HOLIC