I’ve smoked two briskets at a time on my WSM 22 a few times.
Here’s my time line.
Brisket on at 6:00am
Run WSM at 300-325F
Wrap when bark sets ( 160-170 IT)
Pull when probe tender and not by temp.
Brisket cook will take 5-7 hours.
Let rest in cooler, wrap in bath towels until ready to slice.