If you want to use the fav as a Saver bet then you need a Variable Dutching program to bet the Fav so that it breaks even, should it get up.

Fairbot has that facility with automatic input of prices.
You can also Google for a Variable Dutching Bot
Ozracetools has a manual price input version .

Or
Bet all 3 Horses level stakes if Fav is approx 3.00
Bet all 4 Horses level stakes if Fav is approx 4.00
5 Horses with 5.00 fav ect.

You can do this with BBP
Set EXTRAS at say 1st Fav >= 4.00

That way only races with a Fav at 4.00+ will be targeted.

If you are prepared to cop say a small loss if fav should get up, then set the EXTRAS at say 1st Fav >= 3.50
To Bet 4 horses.
That way you get more bets & some higher value on the other 3 horses.


If the others are at a good price it would pay to bet level stakes on 2 or 3 horses where the Fav is 2.50+

Try level stakes out in Sim mode first.
Say 11 runners & less.
Where there is a 2.50+ Fav. using EXTRAS filter.
Targeting 2-3 Horses a race.

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Cheers.