For what it is worth (probably not the paper it is written on!) the following method has been showing >50% POT from start of this year.

It tends to go against what most punters would do, which is follow the "money".

Contender Rules

1. Main Melbourne and Sydney meeting each Saturday
2. Only consider the first 3 opening favourites (and equals). I use Betchoice for the opening prices
3. Horse must ease at each price call i.e. it must not firm at any call

Filters

1. Delete any horse opening at >=$6
2. Delete any races <8 starters (after scratchings)

Results (so far)

Overall
125 bets
36 winning bets
28.8% S/R
+68.5 units Bank
54.8% POT

States Individually

Melbourne
75 bets
22 winning bets
29.3% S/R
+38.2 units Bank
50.9 POT%

Sydney
50 bets
14 winning bets
28.0 S/R
+30.0 units Bank
60.6% POT

This looks easy in theory but the difficulty is when to place your bet. You could place the bet on a horse that has eased at each turn only to see it firm at the death knock which would then mean it was not a qualifier.

I hope someone finds this interesting.