When you posted the tank pic earlier, it didn't occur to me that it would be put on a stand.
I think the stand looks like it should put it at a really good height.
I think the humidity may be an issue with it being open air, especially in an arid area. Are you looking to keep it at a set humidity level for certain critters/plants, or just keep it from being bone-dry?
Looks like it should be a really interesting set up.