Hi, I would start with an Overall Bankroll, then set aside a Session Bankroll, this Session Bankroll would be based on your anticipated run of outs.
Not knowing you betting history but based on my own experiences an using your information, your Base Bet per betting series should be approx $80 then extending to a Max Bet size of $390. these too figures would be a % proportion of your Session Bankroll.
The best idea would be to look at your past history, find the avg Number of bets in each betting series before you have a drawdown.
Then work at what point in your betting series was your maximum bankroll an your minimum bankroll, eg i avg approx 120 races per week that invest i find that on avg my minimum bankroll is approx around the 30-45 races envelope an my maximum is later, with this knowledge you can then adjust your Kelly optimum % to determine your Base Bet an Maximum bet size.