Do I detect cracks starting to appear ?

I nearly gave up on the KH but I have now sunk too much time / effort into it to get rid of.

Hopefully the work I did over winter will deliver what I expect from the bike.

Used bikes epsecially older ones are always going to have issues.

I tend to stick with them and fix them up, but have told me the KH will be the last ever fixer upper, although I might make an exception if a decent MZ ETZ 250 or 301 appears.

Think I would go for the solid state option in your case, as it is cheaper, and is probably going to be more reliable - you can always keep the old unit to sell with the bike when you move it on.