just a further thought on this one, I spent many, many hours trying to turn a slight loss into a slight profit, with a staking plan (i.e. when I got real , I am happy with 4% POT)
The time was better spent weeding out that the types of selections that were definitly not profitable over a long period of time eg. Races for Mares & Fillies only, horses ridden by a 3kg claimer etc etc.

Then concentrating on getting the best possible odds, i.e. say your method shows a slight loss say 2% on turnover, and you have 1000 bets a year of $100 each, so you will lose $2000, for an argument say your S/R is 30% so in this example your average divi is $3.27........ NOW concentrate on getting 10% better odds by using betfair, Best Tote, bookies etc, IF you achieve it, you will return 300 winners @ $3.6 = $8000 PROFIT (8%) talking averages of course! With exactly the same selections!!