I think I found an easier solution.
Got plastic tubs that fit in the wood “sinks” which are simply boxes screwed together from some old shelves I removed. I’ll brush some polyurethane and run some caulk on the inside of the wood, for splashes etc, but the plastic tubs will be actually holding in the water. I may run into issues fitting the drain into a hole cut in the tub and the bottom of the wood box, as there’s no bevel, but I like to think silicone caulk and lots of it will be an answer.
I still have to screw on the deck for a deck mount faucet, and a “wall” for a wall mount faucet, so we can decide between the two types. I also need to bring the base cabinets in to see how high they should be.
This is already helping me figure some stuff out. Like, 13.5” is way too deep for a dishwashing sink. So, I’ll just keep cutting those sides down until it feels right.
These “sinks” might be in use for up to a month, depending on how long it takes us to decide on material for the sinks and have them fabricated. I was thinking of soapstone or marble slab construction, but am trying to look at other choices.