Sorry for the delayed update. Results were pretty good - not perfect, but pretty good. I'm going to call it a B.
Pix:
Not a massive smoke ring, but happy enough with it
Pretty good, but not amazing tenderness on the flat
Sammich - my wife made a BBQ sauce with some of the au jus
The cook was a lot shorter than I expected, but I let it drift down for a few hours wrapped in some towels in a small cooler, which took longer than I expected. Ultimately it was an early dinner.
Timeline was:
~4AM - on the grill. Temps were around 260F
~5AM - I fell asleep.
~6:30AM - Woke up and checked temps - Temps were down around 200F. Commence vent fiddling
6:30AM - 8:30AM - temps range from 230F to 270F
~9AM - Hit 170F and wrapped
~11:15AM - hit 203F. Probe was buttery on the point, a bit firmer on the flat, but still soft. Decided to pull it and put it in the cooler.
4:15PM - Temp in the cooler is @ 140F, and people are hungry. Sliced and feasted!
The point was really good - a fair bit of wow there. The flat was good but not amazing. Overall, both were less juicy and tender than many videos I've seen, but by no means was it dry anywhere and a good meal was had by all. The leftovers were chopped, mixed with the bbq sauce my wife made with a bit of the au jus, ketchup, brown sugar, mustard powder, onion powder, garlic powder, Worcestershire sauce and a bit of water. The next day it was even better.
Lessons:
- I wish I'd kept the temps lower and closer to 225. I feel like this would have yielded a more tender result.
- I'll trim differently next time. I was a bit too aggressive on the fat side, which probably contributed to the less-juicy result
- I'll probably approach the prep and rub differently. I dry-brined the brisket and the Oakridge "Black Ops Brisket Rub" has enough salt that in combination the brisket was a bit on the salty side (though it wasn't as much the next day). Given how long it cooks and the contributions of the rendered fat, I'm thinking I'll skip the brining next time unless I make a rub from scratch without salt. FWIW I've been very happy with the Oakridge rubs on my wings, thighs and pork shoulders.
- I'll do a bigger one and start late the night before. I tend to go to bed close to midnight anyway and wake up around 7 without an alarm. Since I'm feeling decent about having a consistent low/slow temp on my Slow&Sear these days, I think I'll do a 1AM start with a bigger slab (but not max-size for the 22" kettle) and see how it looks when I wake up. It seems like the tendency is to drop down to 190F-200F, which probably? wouldn't be a problem for the end result.
But even this learning opportunity turned into some good eating!
I'll definitely do another one at some point!
Hope this helps other first-timers. I think the net is if you've got the technique down to keep a low/slow cook, you're in pretty good shape. I also highly recommend a remote thermometer to minimize lid-fiddling, but the window seems big enough that it's less necessary than on shorter cooks.