I just purchased a MES 30". I'm planning my first smoke this weeked. the smoker has 4 racks. is the water pan supposed to sit on the bottom rack? I'm doing beef jerky and would like to use all 4 racks. can I set the water pan directly on top of the wood chip box? since I'm doing jerky I won't be putting any water in the pan anyway so do I really even need to use the pan?