What do you look for in a barrel racer prospect??? Do ex-quarter race horses make good barrel racers for their speed?

A good sire is one, a good dam, but you need to look at the horse. I think the ideal barrel horse is.......good bone (not fine bone), sound minded, sound, good eye, good movement,and smart. The ex-race horse is something shows that it had speed, and trainable. The most i look at in a barrel horse is how good-minded it is. if its already hot it might get stupid, a calm horse might get hot but controlable(sp)?.... But thats me