I remember trying this out last year, and I could not make a go of it. But I was only trying midweek not looking at saturday metro.

Someone last year posted similar system (was it d'dog), but instead of the shortest price at each meeting, it was the shortest overall. So left with 1 bet.

Here what I found today using the wa site

geraldton 4 1 fo' shizzle 2.00
echuca 5 1 melanion 2.5
gundagai 7 6 lord de air 2.5
sscoast 6 2 dream speed 3
mudgee 3 2 sir plush 1.5