To tag onto this thought,your smoker will not be finally/ultimately seasoned after the first run.
The more smoke,etc,, you get on those bright stainless walls,the happier your cooker will be.Temps won't bounce around as much on coated walls, and the fuller the load,the more stable the cook will be.
THAT comes with time/cooking.
A butt is the most forgiving thing you will cook,so you'll still get some good eatin'.