It's really hard to find leather thin enough to do these. I made a new bag from rubberized cloth, similar to that available from Porter's. I would suggest, if making a new bag, that you line it with some kind of tear resistant material. Some of the original bags were lined with wool fabric. There did not seem to be any particular model change to account for this. Perhaps a military issue. To use plate holders with sheet film, try to round up some old glass plates (eBay), insert them with the emulsion underneath, or remove it, and slide the film in on top of the glass. That will easily put your film in registration. If you really want to go high class, keep a lookout for an 18 sheet bag mag. I have one for my 3X4 Speed and I can shoot for a week.
