Do base stations just use a standard 1/4" screw to mount onto things? 
I'm thinking of getting a third base station but don't want to put any more holes in my wall, I'm thinking of the corner above my desk, would something like this be a good solution? 
Clamp it to the back corner of my desk, stand it straight up and put the base station on top of it.

Is it important for base stations to all be at the same height or does that not matter all too terribly?