Joe, essentially O'DAY did that around 1982 when they made the hinged mast standard. I like the simplicity of the spliced-in hinge like I show in my posting above, but think that I'd mount it lower than O'DAY suggested so that the lower part of the hinge would rest close enough to the top of the cuddy to slightly compress a rubber/foam gasket or a bead of RTV caulk. The DS has a reenforced "ring" around the opening in the cuddy top where the mast goes through, so a wood or Starboard block would need to be routed out to accomodate that. We have pretty strict Class Rules about these things, so anyone who races or wants to keep the boat "Class-Legal" needs to keep those rules in mind. The hinge is certainly allowed, but I'd be leery about just how much I'd modify things.
When O'DAY made the hinge standard they eliminated the hole in the cuddy top and molded in a flat area for the hinge. They still used a section of mast extrusion as a support under the mast step, but it was not removable anymore.