Katsass
Hi, Katsass, I followed your suggestion on the towel experiment and found it to be true. So I took Tandy's Super Sheen, (because that's all I had) and applied two coats, allowing a few hours for drying in between. Tried the towel again, and none rubbed off. Then I set a sweating glass of iced tea on it for 1 hour of condensation running down the side onto the leather, and there was no water staining marks or other visible marks.
As good fortune would have it, a friend of mine gave me a 3 gallon pancake compressor and a cheap air brush that he had and never used. I just have to get the right adapters to hook the air brush to the compressor, that's probably why he never used it.
Sarge