Johan Bornman wrote:
Nowadays with all the spoke options I am hard-pressed to keep, or
indeed, find stock of all the permutations.

Get a tool to cut&roll your own?

How do they blacken spokes and can this be done in a workshop as
and when needed?

Not in any durable way that would compare to the manufacturer.

--
MfG/Best regards
helmut springer panta rhei