Sigma speedometer on Simson S51?

Good morning,

I recently bought a Simson S51 and now want to make it roadworthy. Since the speedometer is broken, I wanted to use a bicycle speedometer. I now know that this is legally permitted if it covers the entire speed range and is illuminated. After looking for a while, I only find dubious speedometers in the €15-30 price range and I don't want to buy a Koso speedometer straight away. Now to my question. I can't find a Sigma speedometer that is properly illuminated, but I would prefer one. Are they really that difficult to read at night and could that cause problems during an inspection, or can I just install one of these on the moped and not have to worry about it.

thanks in advance