Welcome Tom. I’m just down the road from you.
Some cooks have taken longer for me, others have gone quicker than expected. Many times it has to do with the quality of the meat as well. Prime grade brisket has done fine, and a Wagyu style brisket cooked in 10 hours the one time I bought one. It was 14lbs and when I woke up at 5am it was perfect. I was figuring a long cook given it was 14lbs.
My dad also has a 2 and lives in the east mountains, about the same elevation as you. He has seen short cooks and longer cooks.
But, the way I go is cook until 190 then I open to check for doneness. Based on first probe, I’ll estimate how much longer I need and then check at that point. If you open, you lose heat and it may add a little time. But that’s how I’ve gone about it. As you smoke, you’ll start to get a better handle on it and get estimate hard numbers like you want that will tell you when to start checking. But, even those may be off given that specific piece of meat.
smaller cuts of meat can actually take double the time to smoke. That I have experienced, so I try to stick with larger cuts for pork butt and brisket if I can, then just vacuum seal and freeze left overs. But I remember a small brisket taking nearly as long as a regular size in the past.
But the best part, you enjoyed the brisket as did the guests. So that’s the best end result! Enjoy!