Kevin,
I am pretty sure about the durability of the leather ones. Mine lasted 70 years, at least. The only reason to replace them know is that I pulled off the mechanisms while painting the doors. I like the idea of the nylon washers, just questioning the necessity.
You're probably correct with them lasting a long time, but I don't think leather is the best choice if you have something else available. Not saying the nylon is essential.
All I had left though was the steel rivet when I took my regulators out and the nylon roller seemed like the way to go. I didn't find leather washers readily available either.
