Great price for Choice! Brisket is one of my absolute favorite meats to smoke, but it is very rich so I only do 2 or 3 packers a year.
I usually rub with MSS (Mont. Steak Seasoning), throw on the smoker at 225F, crank the heat up to 275+ when the IT is in the 170s, then take it off when probe tender to rest under towels or in a cooler under towels.
The last brisket I did turned out phenomenal, but I changed a couple things. It sliced beautifully, was juicy thru n thru, and was literally melt-in-the- mouth tender. Even the hunks I vaccum sealed, froze, thawed, and reheated in the microwave are just as fantastic.
Here's what I did. I needed more au jus in the freezer so I did two things different. First, I double wrapped in foil at 180F IT with a cup of boiling beef broth. With the smoker cranked up to 280-285F the flat zoomed to 207F in an hour, WAAAAY faster than I expected. The flat didn't quite probe butter tender, but it was close. I tossed the wrapped packer in a 170F oven for 3.5 hours until lunch.
I expected overcooked, fall apart crumbles when I sliced it, but no. OMG! It was incredible. I believe it was the wrap and 3.5 hours in the 170F oven that made the difference. I had learned recently about longer rests in a 170F oven making a difference. The circumstances of this overnight smoke gave me the unexpected opportunity to test the process. All I can say is it sure worked on my first try and I will repeat it to see if the same result happens again.
Edit addition: If the next packer turns out as memorable as this one, I'll never stand in line for hours to eat someone else's brisket.