I'm installing a new water heater on a floor sloped significantly toward a nearby floor drain. To level the heater, the "downhill" edge needs to be raised about 1". What's the best way to level the water heater? There are no legs on the heater...just a flat metal base. Can I just shim the downhill side, or should I make some sort of low platform? I need a way to prevent the 400 pounds of water pushing down over time from damaging the base of the heater. Any suggestions would be greatly appreciated...Thanks