Some people, quite a few people, use sand in the pan instead of water, to control temps due and for the ease of clean up. I suggest that you learn to use the WSM as it originally was intended to be used and once you learn how to control temps and how your particular cooker works then you can move on to making whatever mods you think will help you.
The vast majority of people do line their water pan with heavy duty aluminum foil before filling with water, it aids greatly in the cleanup.
Treasurer, Great Lakes BBQAssociation
Rubbed, Smoked, and Sauced Competition BBQ Team-
22 1/2" WSM, 2 18 1/2" WSM's, 22 1/2" Weber Kettle