There ain't one.

Been there done it. Had some monster winnings days, AND some monster losing days.
The cost of multiple selections is too high and a day of fav results will wipe you out.

To be anywhere near succesfull you HAVE to take 10 to 12 runners for a place, unless you are a genius at picking 60/1 to 80/1 shots, and if you can do that dont worry about first4's just back em e/w.

Cheers