I have been using fire basket a little different on the last few cooks. I saw one of the bigboy smokers use a basket that was like a maze, i guess because it only allowed a limited amount of charcoal to burn as it went around the maze.
I put a couple of firebricks in like this, and use a small piece of grate to make a compartment to put the lit coal in, it seems to be working, using my stoker, i did two burns over the weekend, one with out meat on sat, that went 13 hours. I firebricks holding a little heat doesn't hurt either.
On Sunday i did a 13 lb brisket and the fire went 14 hours.
Seems to work, the best i could do before was around 10, maybe 11 hours