Hermes, as always becareful has provided some great advice. The first things to consider are your strike rate and average dividend.
A suggestion would be to have say three banks.
First bank - level stakes.

Second bank - percentage of bank.

Third bank - All-up investment.

The amounts and proportions are up to you, but this method ensures that you don't put all your eggs in one basket and are still turning a profit whilst waiting for two or three wins in a row which can be just cream on the cake.

Hope this helps.