7. Rear binding angle.
The angle of the rear binding should be the same as the front binding or very close to it. When the bindings are set parallel to each other, the paths followed by each leg during flexion and extension will be more or less in the same plane. Not only does this create simpler movements with regards to muscular activity, it also means that the leverage created by the boot shells during knee flexion acts on the board in the same manner under both the front and rear foot. It is not in your best interest to twist the board along its length once the sidecut is engaged, as this makes it difficult for the tail of the board to follow the tip. I.e, one end of the board is trying to bite harder than the other, thus, dissonance. Twist will also make straight-running difficult.
The splay angle that is common to many riders is a byproduct of mobility on the medial side of the foot (see section 3) and a fixed stance width. With improperly supported feet, and a fixed distance between the feet, it is necessary to splay the feet slightly in order to feel like the whole foot is comfortably in contact with the ground.
In rare cases, the angle of the rear binding may be slightly more than the angle of the front foot. In my own instance, the bones of my left leg stack better when that foot is toed in by about three degrees. This is apparent when I ride a bicycle, and I have mounted my left telemark ski with the binding toed in. (add photo).