Thanks replies.
It's a multi-purpose goal. To keep it short, I obtained a 645 format custom zoom lens & can get more. I want to determine resolution and whether it covers 6x6 as well, then possibly explore what MF SLR's it can be mounted to. Thus far, only ones ruled out are RB/RZ67 becasuse registration distance is too long.
In the long run, I may either use it with 4x5 SG for round images or depending how nice a job I do on the metal box test jig, that might serve as a permanent camera later. I will probably have interchangeable backplates, one that hold the KIEV back, with separate ground glass spaced to match rollfilm back, and another backplate for a 2x3 Universal/Mamiya Press back that's like a Graflok with it's own GG in it.
SK Grimes is easiest but most costly solution, but not until I establish some 'credentials' for the lens. I think it has some potential, but it's a diamond-in-the-rough as a completely incompatible flange/barrel mount it currently has.
Anyway, this keeps me off the street and I may end up with a MF rig that solves my MF folder headaches :O), and I'm learning in the process.
Thank you all.