Start about four hours before you are going to start the cook.
Make up an injection out of beef stock, garlic and some of whatever rub you want to use. Bring it all up to just below boiling and then let it cool and strain out the bits.
Try to find a packer that is around 12 lbs. Trim off all of the hard fat (you'll recognize it when you see and feel it) and if it has a thick fat cap trim it down to 1/4" or so. Also trim some of the big chunk of fat between the point and the flat. To make finding the grain easier once it is cooked cut off a small piece at the corner of the flat across the grain. That will be your starting line for slicing later.
Next inject the brisket with as much of the stock mixture as you can. Now give it a good coat of rub, wrap it in plastic wrap or put it in a big zip bag and let it rest in the frig for about four hours.
When you are ready to put it in the pit unwrap it and touch up the rub. Then cook it at 250 until it is around 170 or so internal temp or until the bark is the color that you want. At this pint wrap it in a couple of layers of HD foil and add 1/2 cup of the stock mixture (if you had any left) or plain beef stock or apple juice into the foil. Wrap it tightly so it doesn't steam in the foil and put it back into the pit until the temp probe slided in like going into butter (usually around 195 or so). Let it rest in a cooler for at least an hour, cut off the point, slice the flat and enjoy! When you cut off the point cut it into cubes (about 1 inch), add some more rub to the cubes, put them into a foil pan or some foil (leave the foil open) and put them back into the pit for another couple of hours. Once the cubes are nice and dark and almost crispy on the outside you can mix them with some sauce and you have burnt ends.
