Can anyone source the material that is elastic at the top of- for example GG kumo side pockets? I was thinking of my next pack I could fold the material and pre stretch elastic inside but on some trial runs it doesn't look good, it looks real crinkly.

I actually emailed GG to find this out myself and they were very helpful. But I don't really want to share this with you for no specific reason so why don't you send them and an email to find out yourself..

It just looks like 1 inch or so elastic. I haven't seen the pack though, so I am not sure. Elastic will work fine.