Most briskets will run from 8 to 12 pounds, so you've got some really small ones. Don't trim off the fat until it has completely cooked. Each time you open the cooker you lose heat and the cooker needs time to build up heat and readjust itself again. Keep experimenting, and it will get better and better with time. Also, go to some local cookoffs and talk to the guys there whose barbeque you like.
Most cookers are nice guys who are happy to give out pointers.
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