Legitimate conclusions about character can be drawn from looking at a horse’s body: coat condition, weight, posture, muscling, head carriage, tightness around the eyes or mouth, and so on. In other words, subtle signs of nutrition &/or tension &/or muscle tone &/or lack of same.
Hair whorls are handed out at birth. This makes them wonderful for identification. Using them to describe character involves too much predestination for me to buy into. However, it is amusing to contemplate.
Two swirls
Horses with this combination tend to be more emotional and over-reactive than average. They tend to become upset without apparent reason, and at unexpected moments … However, a horse with two adjoining swirls can be a great horse. Some of my very best show horses have had this configuration.
Getting in TTouch with Your Horse
by Linda Tellington-Jones
(Trafalgar Square, 2nd 2009)
p44
Quoted from online PDF. Linking doesn’t work. Google “horse swirls”. Click on “Learning to Evaluate Character – Horse and Rider Books”.
Is anyone surprised that BOTH of my horses are double swirlies?
Virtual Brush Box 
More on swirls here, for what it is worth.
http://horsemanship-journal.com/theory/whorlology/
I read that whorlology article a while back. I found it interesting, particularly Temple Grandin’s statement that the pattern for whorls is laid down at the same time as the nervous system. Maybe there’s something there…
Still don’t buy this, even with the embryo development argument. Given that, it has been fascinating to check out the Saddlebreds. There have been a few who do not surprise me with their serious swirl situation.