Was hauling an old desk to the dump for a friend when I noticed the bottoms of all those drawers were gorgeous ash plywood. Made lots of lens panels out of that and then there was the fiberboard that Dagor 77 packed a couple of ground glasses in, made a few out of those. I need to make several for my 5X7 2d also. Wish I was clever enough to make a 4 1/2" to 4" adapter board but my wood working skills and tools preclude anything that delicate.
Had the old 2D 57 with the Graflex focal plane shutter out today while I was getting my bride a Christmas tree. Had the double Protar VII 9 1/8" lens in barrel so was using that old focal plane shutter. I've found it needs about a 6 pound weight balanced on top to settle that old shutter down. Film will be a revelation whether all this Model T era stuff can still make nice pictures!