Hi X..
depends on my ratings for me..
If i have a standout ratings selection i'll back it for a win regardless of what it is paying..if i have a value selection thats in the top 2 or 3 that i give a good chance and the top 3 are fairly evenly rated i'll then bet e/w ..
Trifectas have been enormous for me..
usually go with a Banker /field bet ..(this has sometimes lost for me even though i've picked the winner..but theres been times i've hit 100/1 shot placings that more than make up for it. selections i wouldnt of dreamed of selecting.)
but if i have only 3 or 4 standouts i'll go 20 to 50 times..depending on the value of the selection..
If i have a roughie i usually couple it with the favourite if its rated highly by me of course..

I have a set amount i bet per race ...if i have a super special ratings standout i'll double this (eg Consular , Yubi , General Conclusion of late)...but i only ever wage 20% of my bank most days ..30% on Saturday's max,,

Having a set amount to bet per race keeps me grounded...i've had days lately where i've started really well..and the temptation is to double ect on other races....I'm a gambler by nature and if i didnt impose these rules i'd be on a downward spiral real quick....

I think with the nature of my type of selections i could do really well with a Kenchar type method of place betting,,,but it would just kill me watching that 20/1 shot win and only having it for a place..havent the discipline i don't think....the upshot is that with my selections i dont need a good strikerate to win...today for example i had a shocker but still only lost 600 ..if i had not changed my e/w on Petrol Head to a win and not doubled up on Mrs Morty i would of won today....with only a few placings and the one tri..

wow i'm rambling on a bit its the beer talking.....
also have a look at target betting...betting to win a certain amount on the race...i've done this successfully but i'm still experimenting with it...
for eg on the weekend i had Fangio , Cellar Edition and Desert Ransome all rated about equal...i backed Desert Ransom (stupid i know ..still bugs me )...but i shouldv'e backed them all to win say 2300 profit..
Fangio 10's $350
Cellar edition 7's $500
Desert Ranson 10's $350

Because you rate all races..you should look at Trebles ...i know its not the in thing ..but check back over your records and see what the divies are ..and see how many you got..you'll be surprised ..

good luck