Is there any way to configure the radius/how far the lamps glow when using colors from a signal?
I already checked the .lua files of the mod but didn't see anything obvious.
My guess is that It's probably coming from the deepcopy of the vanilla lamp.

Correct. Currently the lamp functions in the same way as the vanilla lamp. Maybe in the future I will look into configuration of it.

That would be great.
I'm looking forward for this :)

Took a look at the lua code...not sure how/where exactly it would fit into your style of coding, but these are examples of the lines you need in there somewhere. (These are from a personal mod I made but haven't posted. I used Dectorio's Glow Lamp as a reference when adding and adjusting the lines.)

light = {intensity = 0.85, size = 25}, //sets the default white intensity and size
light_when_colored = {intensity = 0.15, size = 10}, //sets the default white levels when colored (the white area in the center of the glow)
glow_size = 25, //size of the glow (colored) area
glow_color_intensity = 0.9, //intensity of the glow (colored) area
glow_render_mode = "multiplicative", //Optional: I think default is additive, but I found multiplicative to give a better graphical integration with the surrounding objects.