My dock set up also has a boat next to me with just one piling for the stern tie up. I ran a cable covered with a hose from the stern piling to the dock. With this set up if the wind pushes me toward my neighhor the cable prevents me from hitting him. My new boat has a bow thruster which make life very easy.
I would like to be able to run a line up the middle of the double slip, except there is not even a piling in the middle of the slips to tie to. I think the slips are set up this way so that a catamaran can use a the slip- although they would need to pay for two slips I believe.