I guess I envision something like sewing 9 mil plastic into the inside of one of the pouch. I think that would work well. Then you could just dump whatever blend you wanted to smoke that day straight into the pocket and away you go. The 9 mil is thick, so it would hold humidity fairly well and if you roll the pouch up tight I think it would seal off fine for at least your day out and about.
The only other thing I could think of is sewing in a latex bag inside the pocket as well. I think higher end pipe pouches have latex liners in them...
Just spewing out ideas from the top of my head here![]()