Cloudy with a chance of add-on purchase

 I bought another add-on. Not exactly shocking news, given my track record for buying Blender stuff.

CloudScapes: https://blendermarket.com/products/cloudscapes

This looks great for the kind of cloudscapes that I always wanted to create.

A tiny bit of quantisation visible at the tops.

For really big cloudscapes, I'll need to build the scene in layers, then use a compositor to combine 3-4 layers.