I start off a little hot, like this:
And it seems to seal them up pretty quickly, then add in some wood, you can pinch the vents to go lower so your cheese,etc. doesn't melt out......
I use dampened shread & the temp goes down when the wood goes on, but if you're using chip or chunk, the heat may go up when the wood goes on, hence maybe pinch the vents......
That pack might run a good two hours plus, starting @ 300+ & rolling along at 250 for the remainder of the cook......
Happy 'Turding !!!!!