I wouldn't run @ more than 250*, myself. Brisket will benefit enormously from low & slow, and if cooked too fast, it will pass right through the melting pot temps which tenderize all the connective tissues. With smaller packers or seperated point/flat cuts, I've run as low as 210-215* just so it won't heat through as fast and still get the low & slow benefits.
As for foiling, a big yes if you don't want to be tending the rig for 24 hours. I've smoked brisket and pork butts on open grates to finish temps many times in recent months and it increased overall cooking times by at least 1/3, sometimes more. No-foil is great if your after that phenominal bark, otherwise, foil is our friend. As mentioned, during the resting stage, the meat will slowly pass back through the melting pot temps again, and this will further breakdown the connective tissues...a double-wammy, if you will.
180*-185* for sliced and 200* for pulled...if I want sliced flat & pulled point, I seperate somewhere between 160-165*, foil the flat take to ~185* and rest, while the piont rides it out to the 200* mark. Oh, if you're after burnt ends, seperate @ 160* and cube up the point to 1-1/4~1-1/2" and re-season or sauce and smoke 'em for another couple hours...much higher than that and I don't get the texture I'm after in the BE's...slightly crisp bark with a firm popping chew. They're a favorite for appetizers and snacks around our house. You can pull the flat as well, if foiled and taken to 200-205 with some of the fat cap still on...not a standard practice, but it's do-able.
Good smoke to ya, brother!
Edited by forluvofsmoke - 5/28/11 at 12:03pm