Another alternative to chasing the first 3 races for each venue is this.

Target the RadioTAB top 2 selections for those 3 races at each venue.
Stopping once a winner is struck for each venue.

Betting 2 Horses a race.
Use a 60/40 split bet over those 2 horses.
60% of bet on the one you like.
It does not have to be the shorter price of the 2 Horses.

40% on the other.

Stopping at first winner for each venue even if there is a small loss.

Example.
3.00 + 2.00 = 5.00 per race.

Use your favourite handicapping technique to separate.
Try & go for value where possible.

These RadioTAB Top 2 win a lot of races in the first 3 races of the day.

If you can get that 60% bet on the right horse of the 2 , then you will clean up.

Treat it like a 2 horse race.

A number will be odds-on but it is not uncommon to see the other one knock it off a juicy prices.

Some of the winners have been double digit prices.

It may look simple, but its not easy picking the right one of the 2 Horses .

I feel you have a stronger chance of showing a profit doing it this way.
If you strike the right horse of the 2 selections.

Either way , you should not lose much if you consistently pick the wrong one, because you have the other one also working for you.
The SR will be approx 48% of one of these 2 Horses winning.

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Cheers.