I had a late friend who had 2 Vierlings.
First was quite old german (???) built in the expected and assumed normal chamberings of 16/16-8mm-22vierling. Its confiuration was as is the egun listing. The vierling in/or as the top rib.

The 2nd was a grand gun built for him (actually his wife had built for him as retirement present) by Scherling. This in all of its old world majesty was chambered very Americanly i.e. 12/12-.30'06 and 22hornet. On this one the 22H was over the rifle but under the gun barrels. Had a nicely done top rib with a claw mounted 4x Zeiss. Suprisingly light and lively.

I have wanted one ever since.