I rebuilt the ten ports in my 1988 PSC 34 last year. The glass was hazing, and I had leaks around the opening frames and around the glass.
The gasket is 1/2" neoprene round foam. I got mine from
I cut it to length at 45°, glued the ends together with contact cement, and glued it into the ports with silicone caulking. This is also the gasket material that my three Bomar hatches use. It is glued to the hatch with contact cement.
The little screws are brass 4mm flatheads. Some came out easily, some stuck, and some just fell to pieces. I drilled out the bad actors with a hand drill, tapped the holes back with a 4mm tap using first a plug then a bottoning tap, and replaced the bad screws with 4mm stainless flat heads because I could not find brass.
The glass I removed was triplex safety glass. I replaced it with 6mm impact resistant UV resistant acrylic that I cut myself with a jig saw and sanded to final size with a belt sander to leave expansion room in the frame. I set the glazing in butyl tape (1/4" round rolled by hand to 1/8" before installing) from the NAPA store on both sides of the plastic.
While I had the opening ports off the boat, I covered the openings with 1/2" plywood shutters (two small and two large). I saved them for emergency repairs in case one of the ports breaks.