4 to 5 string conversion idea... Thoughts?

The reason I kind of like the gear on the tailpiece, as much as it's an in-ensemble tuning inconvenience, is that it doesn't cram the pegbox the way an additional tuner in there would. Obviously, many 3- to 4-string conversions make it work, but it makes string changes and forelength logistics a real challenge.

 

Martyn Bailey is an expert of the highest order. The Thomas George Martin 5 string basses are gorgeous, I would love to have one.

Here’s an old fiver from Mr Swan’s shop.

However …to me, the modern solution for the classical bassist is just tune in 5ths. C, G, D, A.
Don’t need five strings or extensions.

If you want a high C like the old Kay 5 strings, for whatever your reason, go E, A, E, C.