To all of those who helped this old man, an eight year Egger to cook three Butts on my XL, I say thanks. I did take the suggestion to cook the Butts at 225, which is up from my usual 210, and it shortened the time dramatically. I always place the Guru temp sensor on a bar of my V Rack, so that it measures the heat right next to the Butt. It was only a 12 hour cook. And, needless to say, the XL and the Guru worked their magic. Only popped the hood one time, just to flip. I did use the "cheap" characoal, as suggested by many of you, and no problems.
Again, Thanks. This is a great list, even for the "experienced".
PS: I can't charge my clients for the cook time. Wish I could.