Wouldn't the 'true value' of a horse be what the market prices it at the jump, this being a combination of facts about a horses chances which are known and unknown to Joe P?

A consistent ratings machine being just the starting point for a shortlist of runners which can win, the ultimate filter for those that are most likely to win being the movement of price from PP to open to jump?

LG

__________________
The trick isn't finding profitable angles, it's finding ones you will bet through the ups and downs - UB