I much prefer the results of longer cooks on butts, myself, but that's just our own taste. The longer rendering time at temps in the 225-235 range work magic, and 14 - 16 hours is very easy to maintain using the Minion method of burning. Are these your first butts? If so, then the "Renowned Mr Brown" is an outstanding recipe to use. Go to the
Cooking Topics page and you'll see the Renowned Mr Brown shown 2nd in the "Pork" section.
If you're determined to try to cook them faster, be sure to read the writeup
HERE on quick-cooking butts. I've never done it this way, but others have and have reported good results.
If you don't use water OR sand in the pan for this long a cook, you're going to be fighting temps and choking your fire down to stay as low as you need to be. May as well use the water pan either with foil-covered sand or water, and take advantage of the design that helps make the WSM such a "set-it-and-forget-it" system. I think you'll be happier and more satisfied with your end product saving the empty foiled waterpan treatment for meats that you want to cook at a high temp such as poultry. In THOSE cases that method is GREAT, helping you run at 325 - 350 with ease. That kind of heat doesn't make for the happiest of pork butts, though.
You can't rush good smoked butts. All just my own humble opinion, of course...
Keri C
Still smokin on Tulsa Time