Sorry but I think that any staking plan that doesn't reflect the price of the favourite is just not worth considering. If the market is so accurate (which I also believe) you must bet to return something. Eg bet $33.5 on a $3 favourite but only $25 on a $4 favourite. (Obviously to return $100).
The other way is to bet to make a profit, but this can be quite expensive when the price of the favourite gets too short.

I think your staking plan must reflect this. If your first doesn't get home, increase the return you are looking for.....

Etc... 1st bet to return $50
2nd bet to return $75
3rd bet to return $112.5

Please note this is not a researched percentage to increase stakes, just an example to back up my thoughts.......