In about 1780 Huberty said the future of the Vda was to tune in D, and play in all keys.
I doubt that Fuchs, Götz, or Kudnik had any contact with Huberty, because I doubt Huberty's Method got past the printers proof stage.
But ideas do get around. Here is Galanterie 5, in Bb. Note that for my guys at the end of the 18th century, reading in D in bass clef was so normal, that to retune just the lowest string, they wrote in scordatura, in bass clef. That says to me they played viola d'amore a lot.
Here is a modern notation version of the same passage:
The red notes is just Sibelius trying to help me notice that the pitches I am writing are not on the instrument.
This is a draft for an edition of these very cool solos. I would say the Galanteries were the Paganini Caprices for the viola d'amore. They are certainly the hardest music for the instrument, and they are tiny, lyric poem like expressions.
What do you think of using the bass clef in the edition, sounding an octave higher than written? Is it easy for you to read?