I'm making the assumption that the 16 outhaul is similar to the 14 outhaul - the line wraps around the end of the boom in a channel in the end casting, goes underneath the boom forward to a cleat.



You could probably try the easy route - a loop of strong line around the boom with a shackle that attaches to the clew of the main to secure the boom to the main. The regular outhaul might then still work if you add an eye to the boom on top near the end cap to keep the line feeding properly with angle changes from the sail. You might even add one on the bottom to be sure. If you want more purchase, add some blocks between the end of the boom and cleat on the underside.