The Avus was the "mid-level" Voigtländer plate camera of that time (1930), and came with either Voigtar (triplet) or Skopar (tessar-type) lenses in either Ibsor or Compur shutters. In 1925 the "cheap" shutter was named "Ibso", so yours must be newer than that. But by that time Voigtländer was already using what became the modern standard shutter sizes, so the odds of a good fit to a newer shutter are very good indeed! The rim-set Compur shutter was brand new then, so it wouldn't be much of an anachronism!

The VAG was a cheaper camera, the Bergheil the more expensive one.

Here's one of each of those - a 9x12 Bergheil and a 6.5x9 VAG. Note the Ibsor shutter on the VAG. It takes really nice pictures.