I'm no expert on green egg cooking but have done many briskets in my time. I always have my best luck with 8-10 hours over the smoke at about 225 then double wrap in foil and finish for a few more hours in the oven.
I figured when I posted that a self imposed ruling might soon follow. We go to my dad's on Christmas eve for lunch. A few years ago they asked us to bring salad...WTF? I told Ginny, if they want salad, I'll make them a f'ing salad...I've had to make it every year since.