Great looking brisket! It would be tempting not to tweak your method after nailing it like that, but......if you want the bark to firm up a bit more.... I run an ATC on my 22" with a dry water pan with no serious temperature control issues. I am also not scared to put a brisket in the oven after I wrap it which eliminates temp control issues after the first 6 to 8 hours.
A water pan full of water probably effect's the texture on the bark. It also makes for a messy clean up. Maybe try doing a pork butt with the dry foiled water pan and see how it holds temps and when/if that get's comfortable you can try a chuck or brisket with the dry pan.
Keep on smokin'
