Re: Bedding Deadlights w/ Butyl tape, DC795 and Screws
My CS27 had all deck hardware bedded with butyl and while I am certainly a fan of butyl, I would not use it for acrylic ports. Dow 795 is the best product for this, in conjunction with VHB tape. Few fasteners are needed and after the 795 sets they can be removed and the holes filled with 795. If it is possible to install without any fasteners that would be even better.
I believe that the pressure required to compress the butyl will deform the acrylic. Even with other methods as you walk the docks you see many owner installed ports where the acrylic is closer to the cabin side in the way of the fasteners, leading to a scalloped effect that looks terrible - and that is without the problem of compressing butyl.
Using 2 pieces of acrylic instead of one is a good idea for the reasons mentioned.
Living aboard in Victoria Harbour