Paul, the PPM referred to is a free system that I posted here several years ago, (PPM stands for Partypoopers Plum Movers ) stress only for fun rules are:

SATURDAY METRO 5 STATES

Working up the TAB nos (i.e. No1 is last) take the first horse with a c or d next to it's name that's it.

There are several sub rules that have been added since but not implemented by all.

The other long shot system is working DOWN the TAB nos starting with No1 the bet is the first horse that finished 5th or worse last start BUT was within 3.5k'gs of the winner.