Hi Mac,
Have you thought about betting to Liability.
Say 1/20th of bank.

Example
$400.00 bank at 1/20th
$20.00 liability per race.
Divide Fractional odds of horse into $20.00
e.g. $20.00 divided by fractional odds 4/1 (5.00) = O/L $5.00

The max one can lose, on a single race, is 20.00 regardless of the odds.

__________________
Cheers.