NSPs (not just Lagrange Clouds) will show up after the honk (not sure if before it, honking is a reflex for me), at any distance I believe. The farthest one I've seen was 350k ls out anyway.
Not only do you not need to use the FSS to notice them, using the FSS is actually the worse way of spotting NSPs. (Slower and easier to miss.)
As for NSPs, their rarity depends on the lifeforms they contain. (NSPs are spawned as containers for at least one lifeform, they are never empty. In other words: there will always be one thing that can respond to you, beyond the filler content of crystals and such.) Most of them are quite rare because they are confined to specific places, but a handful are very common. Albulum gourd molluscs in the Inner Orion Spur, various peduncle trees and pods in the Dryman's Point and Sagittarius-Carina Arm regions.
See
here for some maps, although there are some more now.
The way space-borne life seems to spawn is that you need to be in the right region, the right area of space inside the region, and the star & body & other conditions of the lifeform in question need to be met. The reason why the three regions mentioned above seem "overrun" with those few lifeforms is because their requirements are rather lax, and their spawning area covers the entire region.
If you're looking in the right places, you'll find that NSPs spawn pretty well. As far as I can tell, if all the conditions mentioned above are met, an NSP
will spawn, 100% chance.
If you aren't, odds are high you won't see any.
