Get you a Mexican Terra Cotta plate, double foil the water pan AND the plate, and don't put anything in the pan and give it a try. I have NEVER used water in my pan and my meat has ALWAYS come out very moist and tender. It sure makes cleanup easier, and I only change the foil on the plate about every five (5) or so cooks. I change the foil on the water pan according to how much may have leaked down on it.
Water, in my opinion, compicates the management of temperature in the pit. Just the way I cook, and about as many would argue against me. Just saying, give it a try, NO WATER or JUICE, but do put the 14 inch plate (Available at most Home Depots) on top of the water pan. Foil them both and makes for quick and easy clean up.
Good luck.