I'm with Brian--stick to the regular holders for a big trip. I wouldn't shoot anything important until you've tested the holders and using them becomes second nature. On my first outing with a Grafmatic, I left the dark slide pulled out when I exposed the film. It seems obvious to leave the dark slide out when you expose, right? Well, not such a good idea with Grafmatics, since you'll fog the sheets behind the one being exposed because of the septum notches.