Someone made mention in this forum about a system checker which you can use to see hypothetical results given your parameters.

Could you tell me where to find this?

Here are two that may meet your needs;

The Rolls Royce
Winline GTS from The Rating Bureau - http://www.trb.com.au This has all the whilstles and bells you could want but with high upfront and ongoing costs. This one is for the professional.

The Commodore
Price Predictor Pro from Capital Information - http://www.capitalinfo.com.au - high upfront ( depending on version ) but very moderate ongoing costs. Good for the system buffs on a low budget - but with limitations ( ie. can't take into account jockeys and trainers ).

I have some knowledge of PPP - contact me direct if you would like further info.