I've used mine both with and without water in the bowl. The only time I've left out the water is to get the temps higher. If doing ham or poultry, leave the water out to get the temps above 300. It's been recommended to put sand in the water bowl instead of leaving empty to protect against fire, but I have only ever just wrapped the bowl in foil and then afterward, just throw away the foil.
If you've already added the charcoal grate in the firepan, then you'll have better airflow. On the gourmet model, you don't have to worry about easy access to the firepan, IMO. I've had to shake the ash or add coals before and just lift the whole top off of it, meat, water and all (CAREFULLY!) and then I can do what I need to to the firepan. Then just replace the top portion after fiddling. The temp in the cook chamber stays nice and warm too!
18.5", 22.5" OTS
Large BGE (chambersuac's)
The Fiery Furnace (chambersuac's)
Big JT's Smokin' BBQ Competition Team