I used a colored 3D object with nighttexture and tweaked the code, so that it is only visible when the BGL LIGHTS nearly disappear. So you see the colored object in a greater distance. Its not perfect but helps you with the approach. I integrated this colored object in the same code as the BGL-LIGHTS so you have to place only one object.Brightness is not an issue, as it is, I would probably have to limit it.
Papi view distance, while not ideal, is acceptable, and will be pretty much acceptable when I tone the brightness a bit at higher end, so as to make the appearance less sudden (I will take the fallout for "invisible papi" even with it being as much of a simism as it is, that papi are to be bright), but what concerns me more, are the approach lights. Those should definitely be visible from the distances of ~15km in clear nights.
Anyway, I will figure out how to make it all right. Perhaps a terrain LOD with an alpha texture to show AFCAD lights at a distance, gradually switching to BGL LIGHTS as the airplane closes in.