Since the cloth is sold this is Old

so the moderator is welcome to move it as he sees fit.
Several years ago I compared different materials on hand with #10 Cotton Duck Canvas left over from a wooden canoe restoration project. Results below:
Material. Thickness. Thickness at 1:48 scale
#10 Canvas. .034”. N/A
Muslin cloth. .008”. .38”
Drafting linen. .005”. .24”
Rice Paper. .002”. .096”
As you can see, everything is much thicker than the real thing at this common modeling scale. Other scales would be proportionate.
Model Shipways used to sell a lightweight tightly woven fabric called “balloon cloth.” It was used for sailboat spinnakers and possibly military balloons . It appears to be no longer available. I had some that I used for furled sails on a model. Photos below. If this is what Dave is selling, it’s. Probably the best fabric you can find.
Note


that Rice Paper is closest. This is the reason that modelers today are using a similar material- Silkspan.
Roger,