Ok. I prefer whole packers over just the flat.
I usually get 15+ lb. They really are not difficult, but intimidating, and time consuming.
I rub with salt, pepper, onion and garlic powder the day before and wrap with plastic wrap and into fridge.
If I want sleep, I'll put it on the pellet smoker around midnight at 225°, get up around 6AM, and fire up the stick burner and transfer.
I smoke at 225- 250° until the stall, usually around 155-165 ish, then wrap in several layers of foil. I add a little liquid before sealing it up tight. You can use apple juice, broth, cola, coffee, ECT. Only need a 1/4 cup.
At around 198° ish I'll start probing the point. When it's tender, and by tender, the skewer slides in with no resistance. Temp could be 198 to 203 ish. Once tenter I'll unwrap are separate the point and re wrap the flat to continue cooking.
This is important. Let the point vent a few minutes before wrapping in foil. You want some of the steam to dissipate. Wrap the point, and line a cooler with towels and place point in cooler and cover in towels and close lid.
It could take the flat another couple hrs to probe tender, but it won't probe as easy as the point because it lacks the marbling. When it probes the way you like it, vent for a few minutes and add it to the cooler. This resting IMO is very important also. They will stay hot for several hrs. I've had my brisket done early around 10am and guests we're not coming until 3pm, and you still couldn't hold the brisket in your hands without getting burnt. If your making burnt ends out of the point, removed a hr or so before, and chunk up and add to a pan with bbq sauce and back onto the pit for another hr to set the sauce.
I've had briskets cook fast, and had some that just took forever. I've done dozens of briskets using this method, and I've yet to have it fail. I did try a hot and fast method once when my freezer failed and I was pressed for time. On the stick burner at 300°. Didn't wrap, just spritzed it every 45mim. 6.5 hrs later it was done. Point was great, flat dried out a little more than I thought it would but wasn't too bad.