I decided to give clouds another go for rain, or snow, using a simple shape as a curtain mask. It worked fine all through testing with the black card I use to clearly see the streaks, but when I disable the backdrop the cloud layer is nearly totally invisible save for some speckling against the ground, which also doesn't even represent the noise shape. Any ideas why this is? It's a pity because it's faster than a card if you don't use glass.
These 2D hard clouds look decent for pseudo-particles too so I have tons of ideas for stuff like this so definitely wanting to get this working.