Here's a Race I handicapped.
The 1st lot of Odds are my assessment , and the 2nd set are what is available.

1 DEMOUCHI $110 $11
2 ROCKADORE $18 $21
3 SISCO SPICE $4.60 $7.50
4 WOT PRICE PINK $2.50 $2.00
10 LAST ONE IN $166 $26
6 PIPER PALMER $25 $5.50
7 MAJOR MONOGRAM $12 $9
8 MAGIC PENSKI $5.20 $5.50

3 animals are Overlays and are the only animals suitable to wager.
They are 2,3 and 8

Does anyone know a Formula that would work out how much I should invest on these 3 animals.

I don't want a Dutch Book - I know how to do that
What I want is something that will take advantage of the Bigger Overlays.

Simple, $20 on #3 that's the one to beat! #2 is a definite danger but I never bet on more than one horse or dog. (well hardly anyway)

divide 100 by YOUR ASSESSED ODDS, not actual odds

That's fine.
But it doesn't allow for the size of the overlay.

Try this!
We can all calculate the odds of events occurring in roulette.
And what do we find? - the casino pays out slightly less than those Odds.
So if we bet Underlays , we will lose in the long run.

So we must NEVER bet Underlays.
And it follows that the closer the animal is to being an underlay , the less we should have on it.
And the bigger the Overlay , the bigger the wager.

So in the example , the #8 is only just an Overlay , so it would noy be worth as much an investment as the #2 , which is a HUGE Overlay , yet both animals are rated at a very similar Price.

Stiff Lomaca , but you can only win in the long run with handicapping like that.
Is good to see you have improved over the months to where your selections even have my selections a run for their money , and I been playing dogs for over 4 years or so

Didn't quite make it so try the next one it should salute at a good price
race 8 #3 Croxton lass

#2 and #1 might be a danger but as I say, you have to make a decision, no point of betting them all!

I have the 4 inside Boxes running for a very small percentage in the Quaddies on Sandown.

Lomaca.
Thats why I do Markets.
Supposing you narrow the Field down , like you say in Race 8 , to 3 runners.
If you think the top selection is only slightly better chance of winning than the next 2 , and the Market available shows your top selection quite short , and your other 2 at good Odds, it would be wasteful to back Only the top selection.
But you not a fool and you knew that.
Every individual Race has its own peculiarities and they must be accounted for.

One method would be to calculate the outlay as per dutch betting, then increase the bet size as a percentage of the overlay e.g.

Step1 (calculate Bets to $100)

Hse 2: $5.56 @ $18
Hse 3: $21.74 @ $4.60
Hse 8: $19.23 @ $5.20
profit $53.47 if one wins

Step2
Hse 2: 5.56 * 21 / 18 = $6.48 @ $18
Hse 3: 21.74 * 7.5 / 4.6 = $35.44 @ $4.60
Hse 8: 19.23 * 5.5 / 5.2 = $20.34 @ $5.20

2 wins: profit $54.40
3 Wins: profit $$100.78
8 wins: profit $43.50
Loss if none salute = $62.27

I'm sure someone can improve on that for ya

cheers

edit:
Okay so I may have used your assessed odds instead of what is available (slight error on my part) - juust follow the principle of the example

Better give it away for the day I think, need more time to do it justice and the missus is coming home soon.

Good luck

I messed up in Post #4

#3 was the animal that is a Huge Overlay , not the #2 as I posted.