Here's another thought. Why not try smoking your next one at 200°?
I though the same thing, the only thing that worries me is how do I time it so that it gets done on time. like for example they say at 225 its around 1.25 hours a pound.. even though that's not the case for me haha. I'm just trying to find some sort of consistency to get the brisket on the table in time, and not have to let that sucker sit 9 hours and dry out. Out of three briskets only one behaved as expected and that was the one i didn't brine.
Well, my thought was that if you run it at 200° overnight, and then depending on where it is at in the morning increase to 225 if necessary. Pork butts can definitely take the heat of 235-250+ that some people smoke them at, but I prefer the real low/slow for brisket. So, 200-225 seems like a pretty good range especially since you are smoking overnight and do not want any middle of the night surprises.
You are still in the testing phase, and everyone's environment, meat quality, ambient temperatures, etc can influence the cook times. I have found that the best thing to working out the kinks with brisketts is to smoke a ton of them and keep really good notes. With three briskets in, you are still building a pattern. You may find that your differences when smoking in Boise could be pretty different than when smoking in Jamestown.
Oh the fun of our hobby.