Times er hard ta judge cause we smoke by temp, I did a 8 1/2 brisket in 8 hours last weekend, however, another 8 1/2 pounder could go longer. It really depends on the piece a meat. A rough guesstamate is 1 1/2 hours a pound.
I smoke mine at 250* to 170* when I foiled, then took er ta 190*, wrapped in towels an inta the cooler fer bout 2 hours. Mighty tastey vittles.
Yer gonna hit a plateau, a spot where yer temps er gonna get stuck fer awhile, that is normal, it's the meat loadin up on heat, breakin down the tissue, this is how it gets tender.
Sorry can't give ya an exact time fer cookin, it take a brisket (er any meat) as long ta cook as it takes a brisket ta cook. It will be well worth the wait though.