If you are going to start on Friday niight, I would do the butt and bisket seperate. I've done 2 briskets together and it took a while fo temps to rise. I just think doing them seperate will save you headaches (temps and air flow through vessel issues due to size of brisket, etc..)
Check to make sure your brisket fits on the 14.5 grate. Litterally lay the cryo pack on grate to simulate how much space it would take. Go from there.
To save time, you could go hot and fast on brisket.....350 or so. Its an all night cook, so its an experience everyone has sooner or later. With HnF, all temps are slightly higher than LnS temps. In other words if you wrap at 160, try wrapping at 170. Finishing temps will be in 200s, but remeember probe till its like butter. You will get the urge to pull, because of temps, but if it doesn't probe like butter, than its not ready.
Good luck, ask questions.....and pics are welcomed.