I usually follow the Jeff Phillips 'Wooster Brisket' method. He's a competition smoker, has a couple books out, runs the Smoking Meat website and forums.
Wooster Brisket
It is a lot of preparation though, and last time I used it, the brisket was a touch dry for our family's preferences. Today's was just rubbing it down with olive oil, then dousing with the rub. Sat for a couple hours to reach room temperature before moving to BGE. Once it hit 170, I wrapped in foil, left in the BGE til it hit 203 (which is a few over what Jeff's recommendations are). It sat wrapped for an hour before slicing. SUPER juicy and tender, falling apart, cut it with a fork tender. The carnivores said it was one of the best yet. Also....I've come to realize this BGE (XL size) doesn't stay lit under 230 degrees, so I shoot for an average of 250. At 250, it'll run for 8+ hours with little attending, other than playing with the vents. Also, every time the egg is opened, the extra air intake surge....creates a temp spike. The one after 2:20pm...I left the house for an errand. Once back, I closed the air slots a bit, and it somewhat quickly settled to 250 without further intervention. And, not sure why, but I never have the 10-12 hour cook times, even on a full size brisket. The BGE just cooks faster. I'd love to have an offset smoker....but we're out of room in the back unless I make the patio cut into dog's/wifey's plant's territory (and that's a non starter idea).
Here's the final graph before pulling from the BGE:
View attachment 251036
Click to expand...