I did mine about three years ago with polycarbonate. I scrounged around in the remnant bins at my local plastics supplier and found some with UV resistant coating that I got by the pound for about 50% of what branded Lexan cost. On his recommendation I lightly sanded the coating under where the caulk went (also SikaFlex...don't use 4200/5200..polysufide adhesives will eat the polycarbonate). I hadn't heard the "soapy finger" trick so mine look a bit ragged, but they haven't leaked in three years in the damp Northwest.
I see someone installed opening Lewmars? Do you happen to recall which port they were?
Thanks!
Doug.
