Had similar problems when I first started on my briskets ... this is what I found for me, others use different techniques but its all about finding what works for you and going with it.
I spent the past 3 months working on brisket - various techniques, temps, and all that. Finally managed a home run, then 2, then 3, and now really consistent.
Pit temp 275
Brisket Flat injected (Beef broth, Worcestershire)
Sits in the marinades / injection, fat cap down for 1 hour while I bring pit to temp
I pull the brisket out, let it drain for a couple minutes then rub it down with worcestershire. I apply first coating of rub, wait 15 minutes, add 2nd layer of rub. Take meat to the pit and place it fat cap down for 2.5 hours. Come out and flip it over for 1.5 hours then wrap in foil along with a little bit of my marinade, placing it back on the pit fat cap up again. Cook til 195... remove from foil, saving juice, and let it set in the pit for about 20 -30 more minutes to tighten the bark. Bring it in, let it rest for 10 minutes or so and then rewrap in foil, heavy beach towel, throw in warm box (ice chest with no ice) and let it rest for about 2 hours.
Again not for everyone ... but that is what got me a solid product.
Enjoy the cook and love the pics!