I installed the Schaffer lazy jack kit on our Hunter 31 last year and am generally pleased with the setup. In order to use our unmodified sail cover I bring the lazy jack lines all the way forward and secure them to the hooks on the boom. (Rather than all the way aft as Schaffer recommends.) Installation took about an hour in a bosun's chair drilling screw holes in the mast and another hour or so drilling holes, attaching hardware and running the lines. IMHO it was worth the expense and the effort.