Hi, I borrowed my friend's home brewed 5x12 to study before I try making a conversion for my camera. This camera might best be referred to as "brutally functional". It was constructed in a hurry, from available materials, and with no concern for cosmetics. It has however been used to make fine photos so I take heart. In addition to building the camera he kit-bashed the holders out of preexisting components. This seems to me a very clever solution to what I see as the most vexing part of the LF/odd format equation. A "cheap camera" project can quickly bloat when the cost of holders is factored in. However, I don't want to immediately build myself into a corner and in measuring things I find myself wondering: are there "official" specs for a 5x12 holder? I think I would follow his lead to get my project off the ground but, if there is a standard it would be nice to future proof (ha) my project. I would also appreciate any leads and tips people have on sources for machine work and finishing for aluminum parts. Thanks. Celac.