I've tried a flat twice. The second time it came out pretty good. The first time I got a little too busy in the yard and it had dried out enough that it ended up chopped and tossed into a pot to make some impromptu carne guisada.
I prefer a nice packer. The fat down there in the joint does a great job keeping things moist, and adds to the flavor over a long smoke in my opinion. My usual method is to smoke to about 145-150 internal at approx. 200 in the chamber, fat on top. Wrap in foil (heavy duty), leaving 1-2" of airspace above the brisket and raise the temp in the chamber to 225-250. If time is an issue I have gotten away with going up to 275 but then I have to keep a closer eye on things. I pull it at 185-190 internal, I also give it a poke or two with a fork through the fat (mix of science and art). Drain off the juices in the foil for a sauce base. Wrap as suggested by others and place in a cooler.
As for the timing....some briskets will cook faster than others based on fat content, weather, karma.... If I'm not motivated I'll usually try to find a smaller brisket for dinner, and a larger one for the freezer. Pull the smaller in time for dinner, and the larger after the meal to freeze. A great brisket is worth getting up for though, thus the hammock 10 feet from the 'dera.
You can't be a real country unless you have a beer and an airline - it helps if you have some kind of a football team, or some nuclear weapons, but at the very least you need a beer. --Frank Zappa
BOOGITY, BOOGITY, BOOGITY!!!
Recipient of a Huggies box!
Shut up, and cook!!!!