I'm not sure I'd be so quick to discard the idea. My main interest is just to store chemicals from one evening's printing session to the next opportunity, which might be a few days or a week later.

OK, a thin neck will reduce the amount of oxidation, but for my purposes any bottle that's full to the neck will be fine. The worst is having a bottle that's full only to the shoulder. Glass marbles are irritating as you observed, and they have to be cleaned. I thought your pouch idea was a great way to avoid all this.

Anyway, there's a free 1 litre sample pouch on its way to me, so I'll let you know how good it is.