Hi and WELCOME to YT
!! Glad you found us and CONGRATS on Tucker. As for his size, there is no such thing as a "teacup yorkie" - that's just a marketing term that questionable breeders use to sell more. A standard yorkie is a yorkie that is 7lbs or less. It's hard to say how big he'll get, but I'd guess he'll be in the 8 lb range or so.