How it attaches
It attaches to the mast with the two bolts in the left of the pic. I use wing nuts on the front of the mast and the bolts, as that makes is easy to remove them. You should have two holes through your mast where they go. As to getting one made, well mine is the original with some welding mods. I weld so i beefed mine up. If you can weld make your own, if not have someone make one for you. it wouldnt take much. if I was your neighbor Id make it for you. Anyway the gooseneck set up is made so originally the boom would rotate with the sail on it to reef. That is outdated, so boom rotation isnt really needed. I just got me a grommet kit and put reefing points in my sail myself. I run a rope from the tack area of the sail, through the grommet holes, one forward, one aft, of the sail area, and tie it off on a cleat mounted on the boom. Its all pretty easy.