looks to me like the fav with the field i.e 7 bets (quinella)

If one is striking a profitable success rate , why do you need a staking plan other than level stakes or increasing bets in a all up next race type bet.

What you will find, if targeting the Fav as banker + 7 others.
The profits will be break even over time using the TAB. divs

Better margin is gained if using say Betezy or one of their affiliates Dialabet.
They offer best of 2 or 3 TABs depending on venue.
One can even do .10 bets with them, if need be.

Staking plan that can work over 10 bets.
The increment for this is 57% of initial bet = 4 for each corresponding losing race.
7
11
15
19
23
27
31
35
39
43 = 250
STOP

Now , are you sure you wish to use a incremental staking plan.
You need to have at least 3 banks of 250 units, if you are going to do this exercise , other wise don't start it.

Keep going through the ladder until any profit is made.
Then start again.

Repeat any bet that is successful in the way of profit, until in profit.
By doing this , one will survive a longer run of outs.

Longest run I hit was 6 in a row, over hundreds of bets.

Can you say where you pick your Fav from?
e.g. Newspaper , TAB , Betfair?