I've been playing around with some figures on NRL and came up with a system using the stats for loonger term and shorter term periods. I then use these to come up with a high/low chance rate for each team.

Although the Charity sheild is not really played the same way I am going to give it a go.

South Sydney : $2.01 - $2.05
St George : $1.96 - $1.98

I also want to take a safe bet and a risky bet. So two banks.

Risky Bet : St George -3.5 = $3.25
Safe Bet : St George +12.5 = $1.41

Im not worried if this is completely wrong for tonights game but will be interested to see how it goes