I did a small center cut brisket the other day. I seem to remember it was a little over 3 pounds and if I remember correctly I used hickory wood and was going to allow 5 hours. It ended up taking 6 hours and it was only at about 180 IT so I had to finish it in the oven. Also, I ran hickory wood thru the whole 5 hours and it was way too strong a smoke taste. So, I took away a couple of things. One-leave plenty of time for it to do its thing. It is going to be done when it is done and you have to have patience. Two-if your family is like mine, to much smoke is not good. My next brisket attempt will either be a milder wood, pecan, Apple or a combination of wood and the smoke part of the process may only go for the 3 or 4 hours.
Now take this for what it is worth as I am still very new to all this. But that is what I took away from my first brisket. Oh, and the day after the taste was a bit more mellow and it made for a great sandwich. Lol.
Good luck and let us know how it goes.
D