Hi Jeremy, and thanks for the excellent photos and write up yesterday..
Mike and I looked hard at this system, and concluded that it is excellent, but sadly only works for a chute.
As we are both bag sailors, we had to use and older system with barber hauler and a ring and rope system in the pole to hold the guy to the pole.
This stem has two separate guys controlled as shown, which is like the system on Paddy Lewis’ new 505.
It is heaps simpler, but no use with bags – sigh!