You need a balance between cloud depth and cloud density. if you have cloud depth at, say, 2000 then set your density to a small number like 0.0014, edge sharpness down to 2.3 to get an image like the first one here. Also using the density fractal is important for getting the output you want. By decreasing the feature scale and increasing the lead in scale I can adjust the size and distribution of clouds. On the tweaks tab is probably the most venerable of settings for clouds, the noise flavour. Here you can choose between perlin, perlin billows, perlin ridges, perlin mix 1 and perlin mix 2. These will greatly alter your clouds and are a quick shortcut to getting closer to the clouds you want. It's advisable to search these first because if you get your clouds looking kinda right but changing them to perlin ridges would make them better it's just gonna mess your clouds up.
Sorry for the low samples on these. Just used the defaults.
I rarely use the mathematical functions and even more rarely do they work.
