Forrest,
I don’t usually get into making things to sell as this is a hobby. Look through the thread and you will see the three materials I used: PVC, Delrin, and wood. The Delrin is likely the most durable, but I like the wood best. I don’t know how the wood will hold up over time. A potential problem with wood is they may not fit if they swell from humidity
I tried to sell the old PVC set on eBay and got no hits. They aren’t too great but will do the job.
What material would you want and what would you be willing to pay for a set? If you want the old PVC covers I will sell them for $10.