I will try rating a price for each winning chance and wager according to my rated price.But only if the available price satisfies this formula:

Needed price($)=(rated price)^2 x 0.15 plus the (rated price).

Today I went Wagga Race 4 and 5.Warrnambool Race 9.Northam Race 6.

Wagga Race 4
No.2 Red October $1.40 needs $1.70 for $60
No.3 Walk The Beat $5.70 needs $9.20 for $10 (E/W basis)

Wagga Race 5
No.7 Creanced $4.40 needs $7.40 for $20 (E/W basis)

Warrnambool Race 9
No.1 Popeye Doyle $2.25 needs $3 for $45

Northam Race 6

No.2 Brave Jester $2.40 needs $3.35 for $40
No.1 Scottish Storm $3.10 needs $4.60 for $30