Close to a system i've been using for awhile.

Add up the totals of thier past 4 placings
eg. 2x11 tiakun would be 4
x for spells are ok but they have to have a minum of 3 starts
the total has to be 9 or under
and they have to have a Zip rating of 56 or more if there are more than one qualifier in a race go the highest Zip rater.

Today at Caulfield qualifiers were

Lad of the manor (3rd)
Emloza (1st)
Tiakun (UNP)
fast net rock (unp)
Starcraft (3rd)
Regal roller (1st)
solar Antiquity (1st)

in sydney
Stromberg carlson (unp)
Kiawah (2nd)
Rich Megadale (1st)
Red oog (1st)
Capri (unp)
Pyreneese princess (unp)

in Brissie
our sweet moss (unp)
Kengrande (3rd)
Huddle (UNP)

total 16
5 winners
3 placings
8 unplaced

Has a good strikerate but does tend to give you the favourites although Emloza was good value and kiawah for the place was handy.