What colouring is my chinchilla? White Mosaic vs. Wilson White?

So recently a couple fellow chin owners have told me that they're pretty certain my chinchilla is actually a Wilson White, and not a White Mosaic (which is what I've always assumed since this is what he was sold to me as and I've had him for 3 years now.)

I've definitely debated over this myself before but from what I've heard Wilson Whites typically won't have any black tipping on their fur and usually a pure white tail with no grey at the base and Periwinkle doesn't fully fit these...

What colouring is my chinchilla? White Mosaic vs. Wilson White?