You have a choice^, but you have a choice with every ski.
When a ski is made to be mounted center, that means that right in the middle of the ski, right between the tip and tail is where the sidecut is at its vertex, or where the ski is the skinniest. Most twins are skinniest 8-5 cm back from core center... I think scratches held the previous record with something like 3.
Bu yea, invaders are the only ones that I can think of.
innovative innovation, but it is still odd why nobody did it before