Since Durrell Armstrong passed away I have been buying my pneumatic
cloth from Schaff Piano Supply Co.  I noticed that the "Bilon"
synthetic nylon cloth generally "holds up better" than rubberized
cotton cloth over the years.

I service player pianos in the New York City metropolitan area.
I service a lot of 20- to 30-year-old player system rebuildings.
You can get "stung" with a bad batch of cloth either way, but,
generally (I found) the synthetic cloth holds up better.

Bill Maguire