Overnight brisket

Can't help you on timing, as it all depends on what temp you are cooking at and what your cooker's characteristics are.

I've kept brisket for 6 hours no problem. I preheated my cooler with boiling water. Right before the meat went in, I emptied the water and dried the cooler. If you have just one brisket, wrap it with a towel or two to further insulate it. If you have more meat, it should all stay warm that long in a cooler with no towels.

What he said. Ideally, you'd have cooked a brisket before and have an idea of timing etc. based on your cooker and setup.

I do this fairly often. For Cinco de Mayo, I cooked a 7 lb flat on my Big Green Egg. Started the fire at 6:00pm and had the meat on by 7:00pm. Took it off the cooker around 6:45am the next morning. Wrapped in foil and transported in a cooler. Sliced and served hot brisket at 11:30am.

Good luck!

I plan on doing the same thing for one of my archery shoots I'll be running. I did a test run on my Kamado Joe and found that at 250 degrees a 17lb brisket was done in 14 hours. But I'm learning from this site that it's done when probe tender and not by ending temperature so there has to be some deviation based on each individual brisket.

What I'm going to do is aim for my brisket to be done at 4:00am so if it is done later, lets say 7:00am I can still make my time to leave for the shoot. I figure it will hold in the cooler as long as I need or I can start serving sooner if the holding temp reaches 140 degrees in the cooler.