I was able to use my GD for the first time. I made a 9lb brisket, started around 11:30pm Thursday night, and removed it about 1pm Friday afternoon. I did have to relight the fire one time when I woke up to go to work a little after 4am. As I was not awake to watch, I'm not sure what happened. I'll keep a better eye on it next time to adjust air flow. There's just a bit of a learning curve to get the air flow just right.
While the fire was getting going again, I went ahead and wrapped the brisket in heavy foil and put it back on after about 15 minutes once the fire was good again.
However, even with that, I took the meat up to 193 degrees F by lunch time and it was the most tender brisket that I have ever made and possibly the most tender I have ever had - no exaggeration. It did need more smoke (didn't soak the chunks long at all so they went up too quick) and it needed better seasoning - used a store bought rub as I was out of my own.
I did notice one other thing that was never an issue before. When I've cooked briskets in the past, I've always been happy with the flavor but they were never tender enough - poor heat control. While the meat was firmer, so was the fat, so it was easy to cut off after the cook.
This brisket was so tender (fell to pieces when I put the knife to it) that it was difficult to separate the fat, which was so well cooked into the meat.
Next time I will leave only a VERY thing layer of fat, and trim the rest before cooking.
So, while I still need a little tweaking, I can already say that this was an excellent purchase! Next weekend I'll be trying my first pulled pork (shh - don't tell the other Texans).