Cloud optimisation for trial render

[PreRenderedDev]

Sup fellas, I'm looking for a good way to optimise clouds so that trial render times while testing the overall scene don't take ages. I'm using the usual 500x800 image format and 0.5 Micropoly detail. Now I have no issues with 1-2 layers of clouds, but god forbid go 3 and above and render times are hell on Earth. Just want to know what cloud/render settings are best for tweaking and temporarily toning down clouds while still keeping their overall shape.

[Dune]

I think the main thing is AA. Low is fast, but gives grain. Easy clouds are slower too (many stuff inside), and reflections/transparency of surface water increases render time.
My 2 cents.