We have no real plans to breed, so take this with a grain of salt, but I believe it's generally advised to have more females than males and that it's better to get powerhouse males if possible. ie, if you're going for Pieds, you could get by with regular Pied females but would want something awesome for the males - such as a multigene Pied male or a multigene het Pied male if you're confident about the breeder. This is because females take longer to get to proper breeding age/size and because females are generally more expensive. I'm sure breeders can offer much more concrete advice on this, though.