In my opinion focusing on only IT is a big mistake. I have had nearly perfect briskets with IT's between 188 to 206, I have quit temping them and just focus on texture and sag. For example if the brisket is loose and jiggly at 196 why would you cook it further?
As for smoker temp, I was pretty committed to using 235 however I have shifted to 210 for full packers (11 pound average) and butts (8 pound average). I consistently go 16.5 hours before checking. If at that time the meat is not loose enough I run it another hour at 230'ish to push it over the top.
As to running a jacquard through the meat and covering it with fat I wouldn't do it. The brisket will tense up as it takes heat at the same time juices are loosing up inside it. If you provide several hundred holes for the juice to run out it will dry. As to the layers of fat, you are giving up bark in every location you have it.
Goof luck with your meal.