Hi, Frank,
Here in Tokyo, where it is very humid during the summer, I try not to "store" my cameras and lenses. I just put them on the shelf with the rear caps down and put some silicone cloth on them to protect them from the dust by keeping them in the natural air flow. There is no particular reason for using the "silicone" cloth: I just have some which were given gratis from the retailers when I bought the equipments.
That said, my way of storing the equipment would not be recommended for the people living close to the sea, as Keith mentioned.
I didn't have any long lenses, and my lenses didn't fall over when we had that severe one in Fukushima in 2010.