So I'm playing about with the path tracing settings, readying myself for the first render with this option.
My question however is, whether I should adjust / change anything in the Render node's GI in clouds tab?
Does it improve quality or render time? Does it change anything at all?
It changes how the clouds look to the camera. But it also changes how the clouds look when rays reach them from other parts of the scene, such as path-traced lighting of surfaces. You are unlikely to notice much difference, unless your GI quality settings are very low. These settings might affect PT render times, depending on how many rays reach the clouds, but the default settings should be pretty good and you should only be concerned about this if you've increased these settings much above the defaults. Having said that, I haven't tested all this as extensively as I'd like, so it might be worth trying things out and seeing what effect they have on PT render times.
I don't really have a luxury to make any extensive tests, so I just wanted to know if it can improve quality or something. If it's not visible to the naked eye, I think I'll drop it.
Increasing the number of voxels like pokoy has demonstrated seems to influence aesthetic result much better than adjusting GI settings. Provided, of course, that cloud quality and AA is high enough. Though again - I am not sure if the cloud quality has that much significance when PTing.
Cloud GI settings probably don't have much effect on PT, so my usual recommendation would be to stay with the defaults, unless you're rendering an animation.
I have used higher setting on the clouds every now and then, and didn't see much effect, and especially with PT clouds get a bit slow to render.
The one thing I think should show way more effect is going from 2 GI bounces to 3 or more but even this doesn't change much. I guess it means bounces *between* cloud boundaries then, not *within*, as with this one higher GI bounces should technically affect the look a lot more.
Yes, it is *between* clouds, as I understand it.