Is the head/hair really a major heat producing application spot or just and adjunct to the base application? And how do I do it? Do I spray then, flick my fingers through the hair or do I spray several times and let it be? And, as in all cases that I am taller than my target, how do they whiff my scent? Is this spot really effective?
The scalp is, yes but hair itself can be more difficult.
If your hair is thick, it can get much less by way of body heat compared to short/cropped hair.
Also, some pheros, notably Androstenone can bind strongly to hair, giving the potential for bildup/smelly problems that needs a lot of hot/hard scrubbing to remove. So be careful to use products that don’t contain or break down to Androstenone - which kind-of seriously limits your choice to IS mainly.
If you use hair products, this can also be tricky - styling products can also trap pheros/hamper diffusion and many are laden with Triclosan or other antibacterials that will wreck your pheros altogether, so avoid using anything else in your hair.
The problem that causes me to avoid this application route is that the alcohol dries out the hair and makes it brittle.
In other words, no matter the pheromone affect, it is bad for your hair.
You might try adding some to a commercial hair preparation to mitigate the negative effects.