mrad, I think you have received some great advice as far as time, temp and when to pull a brisket. All briskets are edible after 185 or so, but I have never pulled a brisket from a cooker before they hit 205 IT. I don't know if it's my proximity to sea level (500 feet above), my RF pit, my state (Texas, I sure wish we would go ahead and secede!), what the heck happens, but I have never found any of my briskest to be toothpick tender at anything below 200.
As far as temps, I smoke all of them at 250 and above, the old standard of 225, nothing wrong with it, but there is also nothing wrong with 250. As others have stated, anticipate 1.5 hours per pound (not total, but individually), but they may finish quicker, may take longer. Most of all, enjoy the smoke and have fun and for heavens sake, be patient, briskets need lots of patience.