I had a very close call with a knee injury as a result of my binding rotations... ended up hyper-extending my MCL. After that I started looking more into it and of course you would find that you want the most natural stance possible.
The best way I found to do this is to stand behind your board and jump into the air landing on it. Notice that your feet will naturally land in a rotated manner. Align your boots with your feet as they landed, and you should as I noticed feel a very natural movement when you land.
As far as the distance between your bindings I think that is whatever you feel comfortable with.