I just installed one on my Nacra 5.2.
I recycled a broken carbon windsurfer mast and mast base (after cutting off the useless bits). I made a custom bracket by picking up a free strip of aluminum from a scrap metal dealer, sticking it in my vice and banging away until it fit my front beam. A couple of pop-rivets later it was on. Ok, so it cost me two hours to set it up completely, but it weights barely 3kg total.
Dennis