Thanks very much, Olivier.  The tack is supposed to be attached to the chainplates for the lower shrouds. I take your point that the mizzen mast wasn't designed for a mizzen staysail and I'm checking with the designer whether it's ok to add one.  I have had the mizzen up in very strong winds on a reach or downwind so I'm hoping that I won't need runners for the mizzen staysail in light air.  I'm figuring that the max for that sail will be below 15 kn TWS in any event.  But even if I need runners, I have the second utiity halyard which I could just rig to the windward cleat aft, right?  

I also appreciate your point about the risk of chafe for the halyard.  I am intrigued, however, by the utility halyard on the mizzen that exits the mast forward.  If not for a mizzen staysail, what was it designed to be used for?  

Cheers Joerg

PS: I'll be back in LR in April and hope to meet you in person then!