Two years almost to the day, thought I’d bring this back to the front (also, Steak Porn thread seems quiet).
Costco was selling their brined corned beefs, so thought I’d take another shot at pastrami, following what I’d learned a couple years ago. I generally followed the same process as outlined above with a couple minor exceptions:
-Rinsed and soaked the 4.5 lb. corned beef for about 12 hours (draining and refilling occasionally)
-Seasoned way more heavily with primarily black pepper, coriander and mustard seeds (toasted before cracking and combining with brown sugar, onion powder and garlic powder)
-Smoked on Kamado Joe with apple and hickory for around 7 hours at 225 (absolutely stalled at 150 for around 3 hours. Never wrapped but raised the heat to 250 after a while) and pulled at around 175 degrees
-Let sit overnight in fridge wrapped in butcher paper
-Steamed in roasting pan on top of stove until 203 degrees (about 2 hours)
-Let sit perhaps 2 minutes and then started eating. 
The result was excellent. Very delicious flavors. I would say it was not super tender (probably wouldn’t say it was probe tender when I removed it from the steamer, so maybe could have let it steam a while longer. Also unlikely briskets bought as corned beef are even choice grade).
But the most interesting thing to me was how excellent the Reubens we made were. I ate a few slices of the pastrami straight, but my wife grilled Reubens (rye bread, saurkraut, Russian dressing, swiss cheese and the pastrami) and the flavors were amazing. Just so much going on there. I’d was hoping to say the pastrami just stood alone, but the Reuben stole the show.
Interestingly, she didn’t pile the meat up Katz’ style and I think it was better that way. The pastrami had enough flavor to stand up to the other stuff, so it was a smorgasbord, rather than topping to a pile of meat. Even though it’s less impressive, I think it worked better.
Anyway, next year again for sure. Not sure it’s worthwhile to buy and brine my own; this is so easy. But maybe some day…
Mike