This has got more to do with value over S/R.
First,buy The Australian or a paper with the pre-post odds displayed.
Second,identify the top 4 chances.As you know,the top 4 win approx. 80% of the time.
Third,only bet on horses which are double the pre-post odds.
Eg. 1.40 becomes 2.80.{Yes,I know your profit is 4.5 times the pre-post odds,but that's precisely my point.****
I've been out of the country for a while so I've never actually tried it but if someone is willing to test it then good on you.Anyway,remember always to have fun,or sanook as we say in Thailand.
Nick.