Did you run across this article on your research?
http://boards.collectors-society.com...27#Post4534727
It indicates that the boards that are infused with an alkaline buffer give the best protection against acidity over time. These boards don't have a right/wrong side. However I don't know whether fabric deteriorates in the same way as paper, generating acidic by-products. Interesting topic. I still fold my fabrics and stack them.