Our wells are fairly deep, but one would have to have less water in order to prevent leaking and you are right, tilting might reduce the surface area. It would easily work for a dry hatch though which was what I'm wondering. A fair amount of people seem to like to do dry hatches in out bators.The only problem with tilting the incubator that way is that it could make the humidity a bit unpredictable. As the water runs from one side to another the surface area will change.
In addition, I'm not sure, but is that amount of gentle tilting effective?