Around here, the pillow ticking I've seen available is too thin to be used as a patch for a round ball that is a whole .005" smaller than the bore, ie: .495 in a .500 bore. I've never seen any locally I could get over .016" compressed, thus about useless, even for cleaning.
I like .0225" compressed, which I measured and found labeled as 10 ounce denim. The railroad mattress ticking we had here at .0235" compressed was wonderful in all my rifles except for the 14 bore - it likes 12 ounce- go figure. For me it measures .025" with my Mitutoyou mic and .030" with calipers - both compressed.