Ahh...OK, I didn't know aging it made that much of a difference in tenderness. I just finished an overnight smoke of an 8lb brisket. It took around 13 hours, not including a 4 hour FTC. I vac sealed and aged it in the fridge for 8 days. I would have done it longer but that was all the advance notice I had before today's event. Hopefully, it will be enough to help with the tenderness.
I cooked it to an IT of 196*F, at a chamber temp of 210*F. It took nearly 5 hours to go through the stall between 158-170. After that, I put it in a pan, added about 1/2" of beef broth and sealed the pan tightly with foil. I'm not much of a brisket guru, so I'm hoping it turns out nice and tender later this evening.
The only thing I disagree with is adding beef broth and sealing it up. That destroys the bark on the brisket, making it into a roast