A place to discuss the instrument and anything related to it: performances, compositions, educational material, personal anecdotes, questions, thoughts etc.
Be reasonable, constructive and kind.
You might be better off doing this from theory, understanding the notes based on string length instead of taking measurements. Basing it on string tone and percentage of overall string length would let you scale this to any size cello or string instrument.
Now I'm thinking of a hurdy gurdy double bass and that seems like a monstrously ambitious but intensely alluring idea.
On one hand, this is terrible news because I know nothing of music. On the other hand, I expect this will give me a much better understanding of the instrument when it's done. World you have suggestions on where to start learning the theory?
Also, while the music part is still messy, the mechanical part of converting an existing string instrument is surprisingly simple. The biggest problem is getting past the steeper curve of the neck, it makes the key return a bit messy. Other than that, a wheel can be early mounted without much loss of sound and a 90° gear assembly allows ease of play while upright.
The good news is that it's not Music you need to know, it's actually Physics. If a string has a given note and a known length, physics will tell you that changing the length will produce a different note. Unfortunately it's been eons since I've done any such physics, so the best I could do is suggest you look up harmonics or standing waves of strings. It's out there, I just can't think of the proper term.
Oh that puts this squarely in my wheelhouse! This implies there's math and measurements I can do to figure this out! I love math!
Great! Yes, maths are the basis for music (eg double or half a frequency is one octave up or down).
I will return with more questions or the finished product!