It's actually easier to do with Mamiya rb stuff. Get a junked front plate from an old rb67 (they are plentiful) for cocking the lens, and the back rotating plates are easy to find too. How are you going to focus though? The film plane offset on an rb67 back is different than the offset on a graphic or Singer back. I have looked into it and though "Why bother?". I have used rb backs on a 2x3 Speed. That's how I suspected the offset was different. The negatives on film from the rb were just not quite in focus. Kind of like a Minolta 370 I had. I would KNOW I had that image in focus and take it into the dark room and cuss up a storm. The solution to that was called "FM2". Never had an issue after that. Gave the Minolta away to someone who couldn't tell the difference. The solutuion to the 2x3 Speed was just not shoot with a rb67 back.
tim in san jose
I suppose getting a second junk back and affixing a ground glass in the opening with the matte side flush with the film rails would work.
...or maybe some kind of a mirror at a 45 degree angle, with a mechanism to raise it...
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.