The reason why a system should be based around good ratings.

Exactly Darky whether they be speed weight or class ratings.
Then the mechanical approach can start like,
Market position (odds)
Race type.
State.
Cntry metro prov
Track conditions.
Distance etc etc.

The problem starts when you use these factors,
And others to determine the selection criteria first,
Rather than second as profitable filters.

There is a company out there does actually have a couple,
That do make profits albeit it very small when last monitered,
By Punters Choice (Before they shutdown)

I believe this site still advertises them as being profitable.

Would love to list them but you know what will happen then.
T.O.U.

Cheers.