Get the WSM to 275 and put the brisket on cold. I like to spritz with a mixture of 1 part red wine vinegar to 3 parts apple juice. At least once an hour until the color looks like this.
Then I put it in a foil pan with the rest of the spritz and enough additional apple juice to make it about 1 inch deep. Cover then crank the heat. It's done when the temp probe goes in like a hot knife through butter.
I then let it sit for at least an hour or two before slicing. This is the best method I've tried so far.