So I'm addicted to 617 panos at the moment, and I've just gotten myself an 8x10. Put those two together, and I'm contemplating shooting some 4x10s if/when I can. So here's my thinking, I'll load a regular sheet of 8x10 in a regular holder. No need to get a special split-holder and buy 4x10 from the ULF run each year. I get a spare darkslide to modify (I'll have to carry it separately to the holder in use, obviously). I'm afraid that if I just cut it straight in half, it'll work fine in the bottom (shooting the top half of the film), but in the top half it might slide-down. Does anyone do this, and ever have this happen? To get around this potential problem, I'm thinking something along the lines of keeping the darkslide 8x10-sized, and cut out a 3.75x9.5" section from one side. That would leave one half with a full 4x10" solid bit, and the other half would have a 1/4" border around the cutout, to keep the darkslide a bit rigid and stop it from falling down. (I don't mind losing a tiny bit of film with this 'border', my 180mm Symmar-S covers 252mm and this 3.75x9.5" cutout would need an IC of 259mm). Or is that unnecessary overkill work? Of course I'd have to process it as one sheet and cut in half later, but that's actually a plus as it'll fit nicely into my new Catlabs CL81, I'm not good enough to adjust processing on a sheet-by-sheet basis (yet).