From what I am reading is the Mamiya RB/RZ focus screens work well with these cameras but which one is the easiest to focus with? Do they require shims to get the focus right?
From what I have read the Mamiya screens need to be cut to fit. I thought about looking into it but just ended up buying a couple of Rick Oleson’s screens. They fit perfectly and at least in my case did not require any adjustments after fitting. I like Rick’s screens just fine and the price is right.
I agree with Mr. btaylor. When I bought a Rolleiflex 3.5E in late 2016, Mamiya screens were already hard to find. And if you did buy one, you would need to cut it. I bought one of Rick Oleson's screens. On my 3.5E, infinity focus was perfect; no adjustment needed.
My 3.5F had Maxwell screen installed, not sure what adjustments if any were made, as that was part of Mr. Harry doing CLA on still "new" camera back in 200X