I am doing the same to my Pearson 26 -- this weekend in fact. Since it has a headliner, I was instructed to use a hole saw big enough to get a large washer and socket through and I found some plastic (nylon) hole caps at Lowes to plug the liner.
I read an article online of a guy who molded the female threads into his cabin top with the winch bolts, wax applied to the threads and epoxy. It did eleviate the need to drill through the headliner, but I am not comfortable with the epoxy threads under heavy loads. Comments?