We recently lost an elderly beloved family cat that was of regular size and needs. The standard size litter box that you can pick up at the big box stores fit her just fine.
So when Catty came to live with us, we went out and bought her the same standard litter box that we had used...
I don't know for sure about your cat, but I notice that no matter how much a feline looks or acts the part of a certain breed, most cat people are only willing to call them a "domestic short hair" or "domestic medium hair" or domestic long hair". We have, what is almost certainly a Norweigian...
So learning to groom 101 continues as Catty LaBelle attempts to train me in what she needs. I brush her every day now with the aide of patience, much floor sitting (oh my aching 54 year old legs) and bribes of treat tidbits. I've noticed that while she has a LOT of hair everywhere of course...