Hey Dave

It would be very unlikely for the sail to pull out of the mast. bear in mind the majority of the load comes from the downhaul that is pulling vertically.

the main challenge in the setup with be getting the ring unhooked! without the sail headboard twisting the mast wont do anything.

I have read about guys with this setup and they run two halyards, one to the top of the ring and another to the lower side. the idea is to use the second halyard to flick the hook out.

Does not need to be much, a 2mm line should be heaps.

HTH