For those interested, I've just put up a blog post describing my experience of setting up an Arca-Swiss F-Universalis for use with my GFX50SII, a combination that I'm finding works very well with a small selection of Mamiya RZ67 lenses. It can be found here.
-John
Fascinating camera set up. Modifying a board to take Mamiya RZ lenses is a great idea. How often do you use this vs just mounting a lens directly on the Fuji? Your blog images are very high quality.
Thanks for sharing,
barondla
Nice setup but why this over Cambo Actus? What is the cost? Does it work on GFX100s? For now I am using Canon TSE lenses. Limited by movements but much easier setup.