As many of you here in the forums have probably noticed, it is next to impossible to find a decently priced digital back that can fit on a HY6 body.
The only real option I see is making a custom solution to adapt backs with other mounts to it. Namely,the H3D series backs, they are relatively modern, they are extremely cheap, and the H mount is easy to work with.
I've got some ideas on how to get it all to fit and still retain infinity focus, it will revolve around unscrewing parts of the mount and some unsightly 3d printing to hold it all together.
Before I go through all that trouble though, the main thing that I need to know is how to sync the back with the HY6 body. I don't have a HY6 body to work with, so maybe someone here could help me out. My idea depends on there being something like a flash sync port on the HY6 or the lens that will trigger the back. It would work exactly like shooting an RZ67 with cables. I just don't know if it would work, maybe there is some kind of screwy delay, or some messed up signal like on the fuji gx680. As long as I can confirm it will sync up, mechanically coupling the back and the body and getting the right focus should be doable. It will be far from a elegant solution, but I am willing to put up with it. I will be sure to share my findings with the community.