First just a few 7f races from SA:
Note that V/dc and BL/BL dominate at SA. (I only showed columns with significant top 4 percentages.) Several columns only have ones and twos. There can be ties represented here, but usually two horses fill these spots
Then quite a few more from GP:
Note how final odds and CSR dominate for this distance at GP (it can be different for other distances!) Top choice at 7f wins 50% of the time for the period of this model; 67% top two; 89% top three, etc.
This is why I said 7 furlong races using best of last 3 comparable was, so far, the most dependable model.
Get winnin'