Stix,
I used to do this many years ago on track using bookies, but I presume it would work the same using the tab or a fixed odd bookie site.
Take your odds at the 10 minute mark, then bet the following patterns.
Each number is the market from fav out.
123/123456789
456789/123/456789
456789/456789/123
456789/123
The cost from memory was $384.
Gets a LOT of results some small and some very large.
If you get your bet size in profit knock off for the day.
Try to pick races 9 to 14 runners and stay clear of races where there are very short 1st 2nd and 3rd favs.

Cheers