A thankless task, but I will keep a note of the following roughies.
A)First-Starters at $20+ in Metro races saturdays + Public Hols
B) First Starters at $20+ in all others
C) The system referred to by Wenona from Punter57. As the original poster made it clear tweaking was allowed I have done so. The tweaks are as follow.
Metro Races Only (Saturdays/Public Hols)
1)The close-up at big odds (to eliminate) must be last 2 starts, and not before a spell
2) If the horse is First Up/2nd Up at a very much shorter distance than it has won at before, the qualifying runs (the form figures referred to) start from after the spell
3) Very bad "beaten lengths" will not count if before a spell.
4) The price thresh-hold is $25 for all races, as Betfair has many more "over $20" than the totes.
5) The "down two classes " will apply to Group, Listed, Quality, Open/Welter races. Example; down from G2 to Listed. Down from G3 to Quality.Down from Listed to Open. Any confusion, then "down by two" will mean prizemoney reduced by 33% or more, from the lower of the most recent two races. This avoids the usual confusion about classes. Example a class 6 in City at $50,000 may be tougher than an Open in country at $25000 etc, so instead of assessing every race by contestants, the prizemoney will be the guide..
6) A Close Finish is < 1 Length
I will be betting these ones (C) at $5 per horse. The first-Starters is a watching exercise.
If you have any constructive criticisms then I'll be happy to read them. If it's only to say "it won't work" then why not wait ,and see if it won't work, for a month or two?