I run a similar system CP that looks at the PP favourite that also ends up the NSWTAB favourite, I only run it on Saturday Metro meetings but since the start of 2012 it has given me just under 300 selections for a 47% S/R and 31% POT.

However, as it is a system based around the favourite it is very hard to automate since sometimes the favourite isn't absolutely known until after the start so there are races where I simply can't bet because the 1st and 2nd favourite are just too close together. Or the other issue is I see a 3rd or 4th favourite being heavily backed late that ends up running favourite, I can't bet in these races either since the favourite will likely have changed from the time I place the bet.

Favourite systems can be tough to operate but they can be very rewarding, CP is your system based on certain TAB or Betfair or official SP?