Your starting point can really be anywhere. For Brisbane races, I have the best results from the Sydney Morning Herald Newspaper. (Not to good yesterday)

If you have a database or able to produce a system with about 3-4 horses with around 75% strike rate per race, the chances of getting a winnner in each race from 5-8 (quad) is around 30% strike rate. Like any system with a strike rate of 30% the outs can as I have seen go right through to 14, have a winner and then another 9 outs.

Check out my new post for some others systems