As to color and not the material--Made the mistake of using pure white Formica for a bathroom counter. Just don't do it unless you're keen on using a vacuum to clean the counter every single time you use it. Pure white shows every last strand of hair that lands on it. The counter can be clean, as in sterile, and one hair lands on it and it looks really bad. My advice is to pick something that has a bit of a pattern.

Thanks for answers. I am trying to locate a fabricator. My cabinet maker said he knew of some, but couldn't recommend them(!). I'm still waiting for the recommendation from my contractor. I wanted to use a brand called "Vadara", and they recommend I use one of their people. I suppose it might not matter too much which one I pick if it is warranteed.

Whites with swirls are notoriously difficult to seam, making the use of a Seam Phantom, pictured above, even more important. Can they be made better? Certainly. Does he want to do them over? Absolutely not. They aren't good, but they aren't horrible either. You're in a position of strength here, sitting on the balance. Once he pays the sixteen hundred bucks, he'll never have this problem again. He won't like the taste of the medicine, but you're doing him a favor if you make him do-over.

I think it would look great. There are a lot of examples if you google undermount bathroom vanity. https://www.homedepot.com/p/MR-Direct-Undermount-Porcelain-Bathroom-Sink-in-White-U1611-W/311963081 They do make less deep vanities. This is 18.5" deep and has 2 colors and many widths. https://www.homedepot.com/p/Home-Decorators-Collection-Maywell-30-in-W-x-18-5-in-D-x-34-4-in-H-Bath-Vanity-Cabinet-Only-in-Blue-HD2030P1O42-BU/314144506 You can also find them with the tops and sinks already done. https://www.homedepot.com/p/Glacier-Bay-Everdean-30-50-in-W-x-18-75-in-D-Bath-Vanity-in-White-with-Cultured-Marble-Vanity-Top-in-White-with-White-Basin-EV30P2-WH/311606054 https://www.homedepot.com/p/Glacier-Bay-Delridge-30-in-W-x-19-in-D-Bath-Vanity-in-Pearl-Gray-with-Cultured-Marble-Vanity-Top-in-White-with-White-Sink-DR30P2-PG/310163643 https://www.homedepot.com/p/Glacier-Bay-Modular-30-1-2-in-W-Bath-Vanity-in-White-with-Solid-Surface-Technology-Vanity-Top-in-Silver-Fox-with-White-Basin-PPDEC30-WHT/308411271