How do horses get rated on their temperament?
Temperament is very subjective and can depend heavily on what the owner’s experience is. You also want to assume that any seller is exaggerating the horse’s good points and downplaying its faults. I’ve looked at hundreds of horses over the years, possibly thousands. There have been countless times where horses advertised as dead-broke or totally calm (1s by your scale) prove to be very spirited, very green animals. I don’t even pay much attention to the rating the owner gives the animal. I trust my own instincts and impression of the horse. In this day and age, we rely heavily on the Internet for buying and selling just about everything. More people are buying horses sight unseen, which can be both a good thing and a bad thing. You have access to more horses via the web than you might have locally, but you also must rely on someone else’s opinion on the horse. The best thing you can do is look at the horse in person with an experienced trainer to help evaluate its suitability for you.