Yo Mike, What I am about to say may start a flame war here, but I think the added moisture from using a waterpan is overrated. By this I mean, that the moisture content INSIDE the meat is not noticibly different when a water pan is not used. However, the added moisture from a water pan, especially when higher cooking temperatures are used and the water in the pan boils at faster rate, will make a difference on the EXTERIOR of the meat.
I base these statements on my observations from cooking bacon slices on my big offset cookers, both of which use water pans, and my cooking bacon slices on the kettle and WSM using water pans. The bacon cooked with a waterpan tends to have a rubbery texture compared to bacon cooked on a dry kettle or WSM.
Now granted sliced bacon is a thin meat, but I have also noticed that poultry skin is not near as rubbery when cooked with a "dry" fire as poultry cooked when a water pan is used.
Don't get me wrong, I still use the waterpan on both of my offsets, but there are times when I use the dry pan method on my WSM.
Beers to you,
Juggy D Beerman