Chrome Prince- you are definitely dealing with a loser by defining horses' class by evaluating their class as determined by their prizemoney won compared to race starts etc...
There have been innumerable systems over the years based on similar fallacies......they all lose in the short-term(not long-term).
How many maiden races these days pay anything up to $50,000 to the winner, yet, all the winner had to do was to defeat a number of other inferior animals? Subsequently, this aspect gives a distorted view of the horse's ability, even though it only beat a field of plodders racing for exaggerated prizemoney.
Sure, have a go when you think that the odds are too attractive to ignore but the best of luck to you in the long run.

Cheers.