Sounds like you are building a big "Steamer" to steam food.... Something a commercial restaurant would use...
Historically speaking, water and steam were not incorporated into smokers...
Water pans were recently added because commercial "smoker" builders could not control the temperature in their "backyard" smokers..... The water sucked up all the BTU's to keep them from over temp cooking the food....
In my opinion, water and smoke, when combined, make "acid rain" and impart a bitter, "tongue stinging" flavor to the meat..... Something you might consider....
Many restaurants employ steam cookers to cook and smoke meat.... they cook fast and easily control temps...
The smoker you are designing should cook just fine and probably perfect, with good temp control without adding water to the water tray/RF plate...