Well that's the one thing I don't like about how small the mini is on the bottom, for some reason around the 6hr mark I actually have to empty the bottom because it is full to the grate of ash. Not sure if anyone else has this issue but I have had to all three times I have done a boston butt. I usually have to throw briquettes in 3 or so times. Wind or me is a big factor since it's the gold edition, if it's somewhat windy I try to set up a barrier for the wind but it still is effected since the dampers are on the sides. I'm thinking a charcoal ring will help me with a nice slow burn, so that's what I'm going to make this week.
You'll get a lot less ash with lump than with briquettes...especally helpful with the mini.
Hank---- that fatty sounds purdy good! Keep us update when you decide to cook the butt!