Can I just jump in here and ask how long you cook the brisket?
You slow cook a brisket 'til it's done--falls apart when you stick a fork in it. That's the best way I can think to describe it--but it does take several hours, so be prepared to that--and needs lots of basting with a good sauce during this time. It must be kept moist on the outside.
I use untrimmed beef brisket.
Sear Brisket over high heat for about 30 minutes.
Remove and rub with seasoning cover with onions etc....
Wrap in foil. Cover with paper (News or Bags}. Put another layer of foil being carful to seal the foil tightly to hold in juices.
Cook fat side up for 10 to 14 hours depending on size.
I like to uncover for the last hour or so and let smoke get to to the meat while it sits in foil with juices.
Good luck!