Why have a gooseneck at all. The mast is non rotating and the boom can even be totally free handing.

I think it is actually a drawback to use a conventional gooseneck, it will only prevent the rig from totally weathervaning or even being sheet out fully when on a dead downwind course.

As the mast section is round, one can just have a fitting on the end of the boom that is a fork and have that slide over the mast. Well, at least that is how my design has it.

Wouter