Ok, so here is a recap. (Now that I have slept!) Smoked a packer - Sam's Club beef brisked USDA prime, 17.39 lbs. I think it was about $3.60 per lb, so not cheap, but supposedly a better cut of meat than their $2.50/lb packers. Coated with olive oil and Zacks Texas BBQ rub (not that it was a favorite, but it was available at my small, local grocery.) Put in fridge, covered for 4 hours. Put fat trimmings on top of the flat to see if that might keep more moist than my last smoke. (First time ever tried that.)
On smoker (3D) at 1 pm Saturday, temp 225 deg. Expecting to cook 25-26 hours, as last brisket I did was 1.5 hrs per lb, the same as the Smokin-It chart referenced. Checked internal temp - from the 3D readout - every hour for fun. Plotted it up, as shown earlier. Went to bed at 1 am, with temp still at the stall phase (and 176 deg). Got up at 5 am (time change) to check it, and surprised it was 190 deg F. At 6:15 am, it hit 195 deg F - a total of 17 hrs cook time for 17 lb brisket.
Slide the rack out, and probed the meat with ThermoPen. Measured 199 deg in the thinnest part of flat, 195 deg toward the middle of the brisket, and lowest was 188 deg in the thickest part of the point. Prbbed like butter, and super juicy. Had a bit of a time getting it off of the rack as it felt like it wanted to tear in pieces. Wrapped up in foil, and put in cooler with blankets at 6:20 am. Went to bed. Pulled it out of cooler at 10:30 am (4 hrs), and unfoiled to slice. Coolest internal temp measures was still 145 deg in the thinnest flat area (so above the 140 deg concern). Foil about half inch deep in juice.
Removed the fat slabs I had put on the flat side. Still brown underneath them, but slightly lighter than the not covered areas. Cut off about a 2 inch slice from the flat end of the brisket. Cut super smooth, like it wants to tear instead of cut. Set that aside for lunch later. Then trimmed fat and cut up sections of meat to vacuum seal and freeze for later. That's the last pic, but I think it shows just how juicy and tender this came out - even if the pic wasn't presentation quality.
Here are some pics. Note that the first one you can see the meat grain. While it might look dry, it wasn't. I could have easily just grabbed it and pulled it apart. Actually, I had to be careful to keep it in large pieces.
Wife is off to the store for some German potato salad ingredients, and just started a pot of beans in her InstaPot. Both thought we had another 6-8 hours of cook time to take care of that, but no worries. I suspect the brisket is going to reheat just fine.
Thanks for the advice everyone. It's been a while since I've been on here, as we've perfected some killer ribs and prime rib cooks in the meantime, and was reluctant to venture back to brisket after my last less-than-stellar cook. It probably also helped that I got a very good cut of meat this time. But either way, thanks again.
PS. Don't tell my wife that pictures I posted were on that ugly green cutting board! ;-)