Ocho
Every race will be different because of the odds of the three favs.
On the above example laying the top three only. I don't think that there is any gain laying 4. 1st fav win $4. 2nd fav lose $16 3rd fav lose $12 4th fav plus win $24. 100 bets win $860 and lose $500 to come out $360 in front. Betting the fav is a sacrifical bet otherwise you will lose $14 on the fav each time. you only want to have it big enough to break even and be slightly in front on the fav or you will be givng any gains away. If the odds shorten too much then the bet size has to increase so it is a concern but also the lay bets also increase. You can do it manually and get an optimal result but you are better going down the middle road on autopilot. The top three at the above odds give 36 lay bets which would be average and your minimum. If the odds go out too far then you are not going to get even 30 lay bets. Thus you have a minimum odd size and a maximum odds size. Fortunately most of the races are in that range
Beton