Kotobuki Sushi Rice Mixing Tub, Small, Traditional, Wood, Handmade, Japanese Cypress Wood, Moisture Absorbing

Are there any pros that have bought this? If so how does it compare to high quality commercial hangiris?

What is the inside diameter (measured at the inside bottom) of both the large and extra-large sized Hangiris?

Could I rub a good quality cutting board oil on the outside of the hangiri to help prevent wood shrinkage when not in use?

Who is the manufacturer of this (what brand)?