Harness racing there are certain slots that are actually more advantageous I think so they win more often.
Used to make a killing back in the day on harness racing.
For horse racing, we always had the best success when capping the jockies first, then the horses.
@str might be able to attest to the importance of the jockeys, especially in the past.
To truly succeed in the racket of horse racing, it really comes down to who you know over what you know. I doubt that has changed much over the years.