I did two pork butts (9+ pounds each) for my family's annual 4th-of-July picnic and the cook ran about the same time as yours. The Bandit ran a bit hot, about 285-300 or so, and I didn't have to add any charcoal.
This was my ring when I started and I added about 30 lit coals for a Minion start, and a couple of pieces of wood: apple and hickory.
I should add that I run my bandit dry with just a foiled water pan. I also foiled the butts around the 165-degree internal point.
Because it was running hot, I tended to keep the vents almost fully closed through the cook. I do the taps as J'ville noted, and also clear the ash once in a while by opening and closing the vents a couple of times.
Here they are about 4 hours in, just before foiling:
I think the Maverick will be a great addition and that's what I used to track my temps. I believe I read somewhere that the 6' line will work in either port, but I can't remember where that was.
Keep at it; you'll get it. BTW, how did the shoulders turn out? This is what I ended up with and if I had happened to need more coals, so be it! :)