Another shim question

[SimonMaddock]

Hello Sinar lovers

I have one Apo Sironar-S 210 on a Sinar DB board and a Nikkor-W 210 in a copal 1 shutter. I'd like to have it the other way around.
The Sironar has a shim and I'm not sure how to think around this. Is the shim for correcting the element group spacing in that particular mount, or are the mount (db/copal) tolerances tight enough so that I can switch the lens+shim between the mounts without noticing a difference?

Ofc I could burn through a box of film to test this, but I'd rather not. I also want to know the basic theory behind this.

I hope my question makes sense.

[Oslolens]

Did you compare the corners when raised equally amount?
I sold the Symmar-S to keep the 210mm Nikkor-W with 77mm filter threads as the Symmar-S was really ugly on the border of coverage.

Sent fra min SM-G975F via Tapatalk

[SimonMaddock]

I have not. I shoot 4x5 and the border of coverage is at around 10cm shift on the Sironar, where the angle against the ground glass makes it very hard to judge anything.