Hi Sandy-
Still not sure if I will actually build the holders or buy them, but have been wanting to build a 5x12 camera for awhile. In the least I wanted to get the rear standard sized right, maybe make the back later down the road. It'll probably get half finished and sit on a shelf for years. But I guess better sitting there than in my head...That's a good point about the aluminum, I tend to forget that it can move as much as wood. Incidentally, I've seen a bunch of references to .040 aluminum for ULF septums, which seems thin, is that what you're using? It sure would help in keeping the weight down, though. Also, what's the lead time for your custom holders? Thanks again for the help.