Your solution for a better light coverage with the narrow cone mode seems to work pretty well, though it's still a little spotty with brightness set to "Moody"... Anyway, the wide cone could use the same fix. :)

The range of the wide floodlight should not be so high that it would be needed. Full coverage with no "spottyness" would mean a few hundred or even thousands of lights placed per floodlight and I will not do that for performance reasons. When the lighting system ever gets reworked in Minecraft, maybe then floodlights will be better to implement. The current system just is absolutely not made to support floodlights.

The range of the wide floodlight should not be so high that it would be needed.

But, it is:
https://imgur.com/19WC5Gm

Full coverage with no "spottyness" would mean a few hundred or even thousands of lights placed per floodlight and I will not do that for performance reasons.

That's true. But somehow, it works for the Arc Lamp in Galacticraft 3. I don't know modding well enough to understand their code. It's open source in case you want to try and compare how they do it.

The thing is that placing so much lights will probably be not hitting fps until we place at least a few thousands or maybe even tens of thousands. But people on large servers might have a really hard time FPS wise when I would do that. For the extra fix for the dark spots, I will add that in soonish.