moeee -- i wrote the spreadsheet just to answer your initial query -- the formula is very similiar to your approach but the amount/bet is based on a predetermined outlay (like dutching)

would i use it? -- NO
why not? -- i would not be confident that my rating-price could produce overlays in a ~120% market nor would i be confident in the magnitude of any overlay -- the penalty for getting it wrong (big overlay) is severe and would quickly lead to the poor house
what would i suggest? -- if i was going down this track i would use my ratings-prices to "identify" any potential overlay bets then just dutch them

good luck

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never smile at a crocodile -- don't be taken in by his welcome grin

Ixlato - Again , thanks for concerning yourself with going out of your way to help me about the spreadsheet.
Hopefully you at least enjoyed the experience or at least sharpened up your skills so as it wasn't time wasted.

I figure it this way Ixlato.
If you can't get it more right than Joe Public most of the time , then perhaps Rating Runners isn't the way to go for that Punter.

I'll be betting today using this method and I'll see how it goes.
The Problem is that I am involved with Greyhound Markets and the nature of the small Pools is that it is extremely volatile , especially at the hectic , 1 minute to go mark.

I'll try anyway using estimated Markets based on Supertab and Betfair Markets.

Moeee – the Q you asked has broader application and i adapted the spreadsheet accordingly – so the effort wasn’t wasted

How much should i invest? – this could be asked by those who run multiple systems – how much should i invest in each system? – (given a finite bank)

each system has its own edge and therefore to maximise profit and minimise loss it would be wise to allocate/apportion the bank using similar methodology

those systems with the greater potential for bank growth should have a greater proportion of the bank and hence bigger bets relative to the other systems

thx for your Q – it has stimulated thought and discussion

take care!

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never smile at a crocodile -- don't be taken in by his welcome grin