Thank you. Ive enquired about getting a couple of 200mm x 100mm mounts made with 28 x 40mm cutouts and 60mm x 60mm which I would hinge together.
Tomalophicon - how does the 120/135 film stay flat in 5x4 holder, doesn't it bend in the middle. Ive tried 135 with a 120 holder and it's 'ok' but not ideal.