The more you can drill down the better. So if you have the data and can break it out into the tracks, surfaces and distances and type of races you will be far ahead. It all depends on your data and how big a sample of the different things I just mentioned you have. You just have to play around with it. The one guy who could really answer the question for you got banned from the site for acting like a Jackass. Just have to do some research.
Hope that helps.
Handi
