Waterbug, also exploring options for a square top on my 5.5 Uni. I now have 2 pinheads with differing performance characteristics both from the same sailmaker. Go figure.
My challenge is now finding a sailmaker with enough square top design and real-world refinement experience on the 5.5's. If I locate that person, they will already know how to address Nacra's traveler at the foot of the sail with the composition of my mast (carbon).
Let me know what you find.
Sail fast, Tom G