Since “mounting roller ski bindings” has been the top search on this site lately I think it is appropriate to write an article about that, i.e. mounting roller ski bindings.
According to me, roller ski bindings shall be mounted just like cross-country ski bindings, that means on or some centimeters behind balance point. This is so because the maneuverability is best in most situations that way. For the free style equipment the jaw of the binding should be on the balance point of the ski, and for the classic style equipment circa 1 or 2 centimeters behind.
When skating it is advantageous to have the ski level to the ground when it is lifted, and then landing flat when a new stride is beginning. In classic style skiing, and especially when doing the diagonal technique, it is advantageous to have the ski a little tip-heavy so the tip (or front wheel) of the ski easily stays in contact with the snow (or ground) and thereby is easier to direct.
However, many roller skis today are too short to allow for balance point or behind balance point mounting of the bindings if one has larger ski boots than EU 40. This is particularly so on skating roller skis where even EU 37 can be impossible to balance point mount without the heel colliding with the back wheel or its fender. On these roller skis one is often forced to mount the binding in front of the balance point making the roller ski tail-heavy when used. I think roller skis, just like skis, shall be adapted to the length of the skier and thereby also to the size of his or her ski boots, and this is also a principle I follow when building my roller skis.