Looking for info and recommendations on building Refrigerated Fish Boxes

It really depends on what type of boat you have and where you want to locate these fishboxes. As far as preventing dripping, my insulated boxes are scuppered with screened drains to prevent clogging and also have a macerator pump attached to each. They drain out below the waterline through brass thru-hull setups. You could apply this setup on your boxes below the copper pipes to keep the bilge dry. Kind of serves a dual purpose, depending on what kind of bait you have in the boxes. Certain baits provide a constant chum slick behind the boat when anchored or drifting. In a few days I'll take a few pictures and post them here if you'd like. I also assume you have a generator/genset on board to run the refrigeration units? If not you're going to have a gnarly problem with dead batteries.

As for question 3, that highly depends on what you're using for bait. Certain baits work better with kosher salt and dry ice, other work better with regular ice and kosher salt, and other baits work with a saltwater/kosher salt brine mixture, some are best if you don't add anything to them other than cold air.

I noticed in you're from New England. If you don't mind my asking, who is building the boat? You can send me a PM if you don't want it broadcasted via the internet.

Good Luck with the new boat and maybe we'll see eachother out there this summer!

And check yours