Failure! I ended up cooking it too long. The thin part of the flat was dry and stringy. I haven't tried the point end, but hope that it isn't nearly as dry as the flat. At 4:00 I noticed that the temp had gotten above 200 degrees but thought that maybe I didn't have the probe right so I kept it going until 5:15. I just thought that it would take longer than 9 hours to cook a 13 lb brisket, so I was more concerned with pulling it off too early.
Here is evidence of the overcook
Obviously I am disappointed, but I want to try it again and get it right.