Registry Question

All of my graded cards have a number grade, but if I had a card graded as "Auth", can that card be entered into a registry set?

If not, would I just get a message that the card doesn't qualify?

If so, I'm guessing it would count as "1" in the registry, although I could see an argument for it counting as .5 or something.

And finally, can someone link to a registry set with auth graded cards in it? I was browsing and couldn't find any.

Thanks!