My style's foundation is airbrushing, so I don't use conventional sketches as they are more of a general guideline and doesn't help much (or at all) to depict anatomy in the main process.
So my version of sketch I call it 'value sketch', I use just a simple soft brush with 3-5 tones, Smudge Tool and eraser to 'sculpt' the figure or base first, something like this:
sta.sh/0233lknvzxz7
Once the base has been established, I then enlarged them and start the regular painting and airbrushing work, result is this:
As you can see, I use figure number (1).
It's an unorthodox method to start off a work but my gallery should speak the results
Anatomy is very important, it's not just about getting correct proportions, but since I'm doing semi-realism 'stylistic' or 'idealistic' manga style anatomy this step in my process is ever more so important. ;D