IMO - no need for a prime grade brisket. A choice or select have more than enough fat to keep it moist while cooking. To me, BBQing is about taking some of the cheapest, toughest, fattiest meats and making them taste good. Of course cheap went out the window after all the damned BBQ contests and cooking shows. I used to by briskets for well under $1/lb 10 years ago. Yeah - get off my lawn 
Just keep it simple. Lots of good advice given.
BBq and Smoking meats are 2 different things 
Semantics

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To me BBQ IS smoking, while grilling is an entirely different (and HOT) approach. Low and slow with wood smoke to me is BBQ. Smoking (in my mind) can also mean this, but also cold smoking as many do with fish, cheese, etc.
How did your brisket turn out OP?