Nice idea - kudos Birna.
Having now seen what is required, it is a shame that the manufacturer did not already have these grooves included in the collar - not a very hard or costly machining operation with todays NC equipment.
Edit: An even bigger shame that Nikon did not design a mount for the lens in the first place!
Oh well...
My thoughts exactly -- initially. However, they might already have realised that the Z9, not official at that time the 105MC was designed, would conflict due to its shape. As the Z9 is hefty and robust, adding the lightweight 105MC reduces the necessity of a lens tripod collar *for that combination only*. Nikon should instead have delivered something like the iShoot device, but made it rotating in both directions. Due to the protruding camera grip of many modern Nikons only one direction would be feasible for switching from landscape to portrait mode with the 105MC. On the Z fc, either direction is attainable.