Allan, you better buy a film changing bag for a few dollars 🙂 On eBay a seller named "roger_luo" offers some good ones.
I can also recommend Roger Luo's bags, but with some authority. And now that I'm on my 4th cabernet sauvignon I feel like talking at some length about these bags.
My ladyfriend, who is a tailor,
http://www.laurajeanduncan.co.uk/ if you need alterations/repairs in Blackheath, London, examined my Roger Luo changing bag and turned my mild excessive-expense-regret (£17 rather than £8) in to mild self-satisfaction. She says that it is extraordinarily well made, definitely by someone with more pride in workmanship than commercial ends; that the stitching will last and also because the materials are not actually pure cotton but a polyester and cotton mix that should mean a much longer life but with the advantage of cotton. Not much of a business plan if you ask me, but perhaps better value than the price suggests. In anycase I suppose his strategy is understandable if you consider he is a small fish in a big sea with no desire to tool up and make factory (nor much reason to do so).
She added that it would have been much more expensive if I had had her make it, to which I was able to please myself with the thought of Roger Luo's claim of "with much attention to functional detail" or words to that effect, that she could not have assumed for herself. I'm supposing that it's design has been tweaked with usage experience though I'm not in any position to judge that claim.
In any case for me it seems to have worked out: I got it because of warnings of sweaty hands in cheaper bags and as a beginner I knew that would probably undo me and so I had to spend the money. Since beginning I've had some hair-raising experiences that took a while to sort out and no sweaty hands (UK summer, pretty mild here). Functional detail doesn't mean light won't go in if you remove your hands: so don't do that (except in a cupboard, perhaps).
I can also add that for 35mm shooters putting a 30m roll in to a bulk loader in the smallest of his bags is just fine. Also that it is fine with a two reel Patterson system 4 (not super, I haven't one to try). There seems to be quite a bit of room. I also opened a camera and loaded a reel just fine in to the Paterson. I couldn't find this kind of space/size info but risked getting the smallest bag; so hopefully someone may find this info useful and share my joy in saving a few pounds.
And while I'm feeling over-enthusiastic I recommend to all fans of St Francis to see Franco Zeffrilli's movie "Brother Sun, Sister Moon" life of St Francis. I'm also starting a novena for this fellow at
http://novenaforfrancozeffirelli.blogspot.com/.
Now, where's that bottle gone....
