The hairy areas can be problematic, agreed. With this treatment I got almost immediate healing effects on "naked" skin, the SD in the beard and eyebrows took a few days more to heal.
Using oil with salt doesn't seem like a good idea for the scalp, the salt crystals will probably be quite rough to the hair. Maybe the olive oil can be used as is but it will be messy to use as a regular routine. I'm lucky enough not to have very much SD in the scalp nowadays so I can use standard dandruff shampoo effectively (Head & Shoulders, etc).
To me it seems that the elimination of the SD from my face also had a positive effect on the occasional SD tendencies in my scalp. The reverse is known to be true as well, controlling scalp SD and dandruff is an important factor for success in facial SD treatment.
In short: for SD problems in the scalp, I prefer the standard anti-dandruff stuff. When it was a real problem for me, I used ketoconazol-based shampoos to great effect but I don't need that now. I would not hesitate to use it again if the problem shows up.
Speaking about the salt component, I'm not sure why this made the olive oil treatment more effective - is it the abrasive peeling effect, or is it the salt and its supposed anti-bacterial (and anti-fungal?) effects? Maybe it could be both, I don't know. Later on I will experiment with that to learn more about the mechanisms that are involved.