I saw your post and was shocked. I had the EXACT same question to the group myself. I wanted to order from Century Farm Orchards and they only sell trees on 2 different rootstocks (and I don’t graft for medical reasons). That thread is here
After a lot of research, and as much as I love century farm orchards, if you don’t graft I would recommend getting a custom bench graft from 39th parallel nursery instead. He will custom graft any of his apple rootstock to any of his apple Scion wood for you, and mail you the resulting tree. I’ve gotten 10 pear trees this way on rootstock that aren’t available on at any other nursery in the Scion to rootstock combo I wanted. I’ve even had specialty pear cultivar Scion wood mailed to me from Georgia, and then mailed that Scion wood out to 39th parallel to graft for me and send it back.