Amazon had a watch crystal protector for the Casio Duro for $8 and I decide...why not. They fit perfectly. My beater watch has not had suffered to many scratches, but the case has. Maybe the crystal protector is unnecessary, but for the little cost, why not?
Apparently the same material. Here is a link for what I bought. https://www.amazon.com/dp/B07CKB4FGJ/?tag=thshde-20
Did you try heating the strap with a hairdryer or such after applying the wax? I find it really treats the fabric as it lets the wax penetrate deeper.
I thought about it but no longer have a heat gun or a hair dryer, so I hand warmed it and went with melted wax. Figured I'd try to heat-treat it a little later on. Should end up having the same or similar result either way.
Standard practice is not to wax the inside of the band, right? I don't see it feeling wearable if I do that.