The more important question is how to achieve a tastier, or juicier brisket. To me, that means leaving all the fat on the brisket, and I don't trim my brisket anymore. All I do is wash it first, then use a use regular cooking oil after is dried up, for holding the spice on the meat. I always set the meat fat side down, and I never check it unless the inside temp reaches 195 degrees. ( I use an ATC) Once the meat is ready (between 195-205 degrees) I separate the point, and smoke it another 2 hrs, while I let the flat set in the cooler for 2 hrs.
I never have any problems with having a dried up brisket. My brisket is juicy, and after I take off the point....there is hardly any fat left on the food. I often wonder how much fat is melted away form the long cook..? I usually cook around 225-230 degrees, and I love to do it overnight, for a next day lunch.