Yeah, I kinda wish I wouldn't have cut this brisket, but thought the whole was to much for this gathering.
Also I am rethinking the sauce routine. Watched some video of people spraying with apple cider vinegar mixed with water. What does this accomplish? Also a couple with people injecting with beef broth etc... any of you guys tried that?
I always recommend trimming a whole packer where you remove the thin portion of the flat like the following image. This will cut down the size of a brisket quite a bit AND will help ensure it cooks more evenly without losing that thin meat to burning/drying up. This may help you cut down the size of your briskets if a little too big:
I'd highly recommend not spraying, spritzing, mopping, or doing anything like that with a whole packer brisket or the point. It just prolongs the cook with marginal if any benefit. If just doing a brisket flat it may need some spritzing but I would simply just wrap in foil with a couple ounces of some liquid at some point around 180F IT or when it looks like it's getting a little toasty. I do this with chucks which are similar to flats in the regard of wanting to dry out if done unwrapped too long.
I do my whole packers unwrapped the entire time BUT I now smoke fat side down and then lay some trimmed fat on the top meat side (meat side up) around the edges of the flat and just all over where it will fit. Nothing too meticulous but just kind of a protective layer that keeps things basting with wondreful beef fat AND... I get beef fat cracklins made from that fat at the same time as it dries an toasts up!!!!
As for injecting, you could but again it's unnecessary on a whole packer. A lot of that mopping, spritzing, etc. is very much unecessary and is just prolonging the cook. If you're looking you're not cooking!
Finally, a brisket doesn't care what temp you are cooking it at, as long as you are not burning it. Same applies for pork butt, ribs, chuck, and beef ribs. So feel free to crank the heat up! I go 275F on mine and would go higher if my smoker supported it :D
I hope this info helps :D