Thanks Russ, much appreciated.
The way I do this may not be the most natural/realistic, as the areas of rounded soft snow is by PF mask and not derived from mountain shapes, but I think it's quite appealing anyway.
First one is an updated version of v3, second one (v4) is with just a different 'snow fractal seed'.
Again, no compute anything used, so the big one renders in an hour at 0.7 and AA 8, soft shadows at 5 samples.