Yepp, the video itself is quite good, the idea with the "key-hair" for special effects is definitely something to copy into my own concepts.
I'm using normally 3 particle systems, all placed on different segments, so I now learned that I only need one second layer and it will work as well. If you want to pose your character, always keep in mind that you only can comb one system at one time. And I'm sure, that for this character bald parts at the back of the head (only one "ring" of hair at the top) will appear, when you change the pose to e.g. "lying sideways" and comb the hair down.
And we should remember the best idea from Wolgade. Typically, the artist pushes down the inner layer to get the hair near the scalp. I've done it the same way in the beginning. The better way is to select only the root of the appropriate hairs hit one time "ctrl num +" to get the first segment selected and subdivide only this segment. Then repeat this. So you get 2 more segments from the root of the hair, two of them 1/4 of length and one 1/2 length. This allows a curve near the scalp.