Try this staking approach for betting 2 horses a race .
Start off at 2 units on each horse , now increase the previous bet by 50% .

Repeat bet if a winner is struck but have not fully recovered loss.

The objective here is to strike 2 winners in a row & this should recover all previous losses.

Increase the bet to a max of 7 goes before sarting from the begining.
The bets on each horse would look like this.
E.g. 2,3,5,8,12,18,27=75 X 2 = 150

The reason why we set this to 7 goes before ruling off is because the medium average outs is 5 ,it also helps the bank from blowing out of controll

One should have at least 3 banks of 150 to do this exercise.

The longest run of outs that you should expect with a 45% SR is 12 in a row.

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Cheers.