The Violone (Question for Early Music Specialists/Anyone, really)

"Violone" is used for several instruments mostly but not entirely consisting of viol with some early violins included. If I'm transcribing a baroque piece, I adjust the range to to the appropriate violone and change the sound in the mixer as needed. I'm currently working on Handel's oratorio Saul and it seems to have both the cello range and double bass range in different sections and both simply called violone.

Wikipedia has a little info on it. https://en.wikipedia.org/wiki/Violone

First: I'm not an expert!
Just I want to write what I know. (or what I think I know):

There are two things we can be sure of: (According to my notes)
It isn't possible to have Contrabass in Bach's works before 1717.
It is possible that he used the Contrabass instrument in his works after 1723.

At Bach's time the Harpsichord players played the Bass part with the left hand, And there was a Cello that doubled the bass part from the octave below. (named: Viola de gamba or Basso Continuo).
The Harpsichord player was instantly plays the harmony part aslo, by looking only at the ciphers. (Figured Bass)

If the piece is for a larger Ensemble, then the Contrabass was added to the octave below. (If not has a separate C.Bass part) (at that times an large ensemble has may be 20 persons or less)

According to a story I heard during school years: At that times, an orchestra conductor said: "Contrabass player must know how to accompaniment." It shows that (if its true) : Most of the time there was no special part for Contrabass. But the Orchestra also had a Contrabass player.

But there is never a 2 octave gap, between the left hand of the Harpsichord player and the Bass instrument. (or between Viola player and the Bass instrument, for Ensembles) There must be a Cello between them. (Or just Cello, no Contrabass) //Though there was such a tradition, I do not think Bach used it.

At Bach's time: Some intermediate model Contrabasses (6-string) had almost both C.bass and Cello's note-range.

His works, were copied and published by the son (C.P.E.) and others. That it's inevitable there would have been some mistakes. (Including the octave problem.)

I don't think we can solve the Instruments confusions, used in Bach's time.
There are only some estimates and expert investigations.
And each expert has a different idea than the other (and this is something to be expected).

Maybe it's better to make your own decisions about the works.
After all: Since you work so hard on these works, you are also an expert. :)

... and, if today, you find yourself doing such a thing, you very well might be replicating what "your now-ancient contemporary musicians" might well have been doing at the time! Musical scores were, after all, very-necessarily prepared for use by "then-contemporary human(!)" musicians!