IMHO - It seems reasonable to me that out of 20 young and maturing colts at least one, probably a couple, will jump up to a new and improved performance level.

Secondly, and I think primarily, which Colts can run their existing tops at the longer distance?

Predicting the trip is also a factor; it can beat a horse, but its hard to imagine it causing a horse to win.

I will repeat my opinion about the Japanese racehorse industry. In the land of the Rising Sun, earthquakes, tsunami's etal they breed horses more for stamina and distance racing than sprints and speeds. They also train them accordingly.

If you've ever watched the Japanese races late at night, they are running maiden races at a mile+1/4 - Mile+1/2.