What size bedding?

I agree about the jersey sheets but before I found them I placed a fitted bottom sheet on the bed and pinched up the excess amount to see how much smaller would work well and sewed a pleat all along the bottom. Before that I sent for some expensive sheets made for that size, I ended up throwing them away as they felt awful.
I had some full sized flannel sheets that I added a strip of fabric to so they were a little larger and they also work just fine.
My experience with the made for RV sheets was ten years ago so perhaps they are better now.