The key to cooking a good brisket is to keep it simple, get you a COW POKE Themra pen and cook it until it is probe tender in the thickest part of the Flat. If the thickest part of the Flat is Probe Tender the rest will be perfect.
COW POKE Themra pen
BBQ RULES FOR SUCCESS
YOU CAN NOT COOK GREAT BBQ ON A CONSISTENT BASIS BY COOKING TO AN INTERNAL TEMPERATURE OR BY TIME ( XXX MIN PER LB) YOU MUST COOK BY FEEL! For Brisket it must pass the poke test(probe like soft butter in the thickest part of the Flat)
Ribs pass the Bend Test, Pork Butts when the bone wiggles loose. These are the only reliable methods to ensure that your cook will be a success. There is one exception to these rules and that is Poultry which must achieve and internal temp of 170 deg in the thickest part of the thigh and 165 in the breast