I do remember a stat

Days after a spell of 90 days+ (1st up record)

Races up to 1300m - approx 15% Win
Races over 1300m - approx 3% Win

Don't have my database with me so could need verification.
Horses don't usually win the longer distance races 1st up vs the shorter distances.

The best strike rate I believe was

1000m - 1600m = 3rd up horses around 21%
1600 m to 1800m = 5th up horses around 17%
1800 m + 6th up horses with around 18%.

If someone has time they could calculate this with detail.
Barny probably has all the figures

Cheers