CosMos,

So essentially the age, distance change, Days Last Start and Career Starts filters can be applied to any maidens straight away to narrow down the field on a simple spreadsheet.

The time consuming part (as far as I can tell) is looking at the sire, dam etc etc in terms of your grading. I honestly have about zero idea when it comes to the breeding etc so this is all new to me, but I assume you look at various stats of the parents/grandparents to work out the vaibility (grading) of the horse running?

This essentially means that your grading technique is what sets your selections apart as anyone could add the other filters above with ease.