Why do they have to be stainless? The reason I ask is that to
the best of my knowledge, no one uses stainless as a deco ring.
There's aluminum (certain alloys polish quite well), German-
Silver or aka Nickel Silver and it doesn't contain one molecule of silver.
Lastly is the ever-eloquent Sterling Silver.
You'll likely have to cut from sheet as I don't know of anyone stocking that thickness.
Aluminum for the most part, is what is used for a variety of reasons.
Have you ever weighed a NS ring? It adds up quick.