first determine your true bankroll, your bankroll in play, and your goals (ie winning % versus avg juice you will lay) and keep in mind, your goal does not have to reflect a positive number. just a good modest estimate of where you think you will land.
Divide those numbers in half and use 2% of your bankroll in play as your unit size, adjust that 2% by your winning percent at the end of each week, and keep your true bankroll (replenishment funding) at absolute minimum