Time ago i have been helped by a very kind fellow member, with scans of the two missing "tea strainer" rings for my barrel Imagon 300mm.
I had in mind to copy them in black cardboard, but i gave up, waiting for metal caps that could me modified to imitate an original Rodenstock ring.
Recently i purchased a 420mm Imagon with NO rings, and if i can find 1:1 scans of the original rings, i think i will dedicate some of my spare time to the fabrication of metal rings, both for the 300mm and the 420mm one. There are metal caps that are available at shops specialized in wine production supplies. I hope to be able to modify them as replacement rings, but i still have to check if they store the right diameters
I hope to find an owner of a complete 420mm, who's willing to scan the rings, and email me the jpeg's. A barrel Imagon, without rings, is not very flexible, as there is no diaphragm, so i hope that somebody would help me.

Of course i am also willing to buy one or more original rings, if somebody has got them in some drawer...

A small side note:
the main reason behind my purchase was that the Imagon came with a large diaphragm lens holder, something that was probably missed by many Ebayers, because the holder was partly hidden behind the lens. What amazed me when i got the lens in my hands, was that the lens holder was different from all the others i own or i have seen in picture.
The holder has the conventional diaphragm leaves at the front, while at the back there are threaded clamps, solidal to the leaves, which allow to hold firm any large, heavy objective, even those that have the flange thread at the back end (and almost all the weight at the front). The kind of lenses which are, unlike the Petzvals, very difficult to be firmly blocked by a diaphragm lens holder.
Anybody out there owning the same kind of lens holder? Are they common, any more infos about them?
Thanks

have fun

CJ