What Wally is saying is good advice, of course. However, I tend to place no limits on any race other than no hurdles, steeples or untested 2yos. That's it, come what may after that. You need to IMO, for AUS races through the week. There might only be 3 meetings on, by the time you eliminate soft tracks, synthetic tracks, maidens etc you might only end up with 3 or 4 qualifying races.

The data I grab, is one size fits all, pretty well, and the analysis is on that basis, so it should all average out in the end. The more filters you apply, the smaller the sample, the less reliable the analysis. Apart from the race types described earlier, I just use Price, Volume, and two free Ratings. Most, if not 90% of the variables, are taken care of in the consensus of those four factors.

So keep it simple to understand, work out and your punting life will be a lot easier. I'm sure the fastidious types will disagree, but each to their own.