Originally Posted by newbie_smoker
It is my understanding that water instead of a foiled saucer or sand actually helps control the temp BETTER as it will act as a heat stabilizer whereas the saucer or sand will just heat above and beyond the 212 point of water. Clean-up isn't a big deal at all. I've just heard that water works better for temp control.
I think if you try running with just a foiled water pan for a handful of cooks, you'll figure out the same thing most of us WSM owners do--it doesn't need much help to maintain temps.
incidentally, if you are doing pork shoulder, I wouldn't worry too much about the temperature--they're very forgiving, and difficult to mess up.