Only a small suggestion from me:

Because my eyes are pretty bad, I play Factorio with HEAVILY modified client side graphics files (I just overwrite a ton on PNG files in /data/xxx/graphics with my personal PNG's) and the "on" light graphics (file being "hr-lamp-light.png") was one of them, to offset the visibility problem that you have changed in your Mod for better visibility.

My hack is a quick/dirty one, all I did is just make the entire lamp shape contour SOLID WHITE (I could have been more artistic, but that was not the point)
If you have more talent, maybe just make "hr-lamp-light.png" brighter as well in your own mod? It would add extra contrast on top of what you made already.

But also, thank you for making me realize that darkening the base "lamp.png" also helps with contrast. I had not thought of that and now I'm also going to darken that file for myself for my future games.