I ordered a handmade sink for our house. The drain hole diameter measures 1-5/8" exactly. I need to purchase a grid drain assembly for it and am not sure what size to buy. I called the person who made the sink and she recommended a 1-1/2" assembly - said that size works for all of her sinks.

I never majored it math, but I know 1-5/8" is > 1-1/2".

Do you not size the assembly to the hole?

I would appreciate any help. This is not my forte! My next step will be the plumber, but I thought... surely something as simple as a drain assembly I could manage... :(