I cooked two butts for our July 3 party using a Minion Method start of original K and a pan of room temp water. All vents wide open, meat was stone cold from the fridge. All vents wide open. I checked the lid temp every so often...212, 256, 256, 262, 262, 270, 276...when first butt hit 165*F internal, it got foiled and moved into the oven set to 275*F. Over the next 40 minutes, after the removal of that first butt, the cooker crept up to 290, at which point the second butt had hit 165*F internal and got foiled and moved to the oven.
As you can see, I'm not too uptight about cooker temps, and pork butt is so forgiving it really doesn't matter for a backyarder like me.
But if I wanted to maintain a low temp for a long time followed by a bump up to 300*F, I think I'd lift off the middle section, stir the charcoal to remove ash and assess how much fuel I had left, perhaps have some extra lit charcoal off to the side if I needed to add it, then reassemble and open all the vents to get the temp up, but monitoring carefully so as not to really overshoot that 300*F goal.
But moving it to the oven is a lot easier. Putting it on a small rack in a foil pan then covering with foil works great, the rack keeps the bottom of the butt from sogging out and you can pour the juices in a fat separator and use the liquid to flavor the pulled pork. Yum!
