To calculate the max profit you can risk without getting broke ("risk of ruin"), generally the kelly criterion is being used. Truthfully I personally do not know the real details of this complex theory/formula :> But generally "0.5 - 1 times house edge is being used". So if your bankroll is 10 available coins and your house edge is 1%, you can risk 0.05 - 0.1 max profit per bet. If a player is lucky and you have 9 coins left, this should change to 0.045 - 0.09. You can use 0.5x or 1x depending on what you are comfortable with.

Is 10 btc bankroll enough? Well it depends if you think players are fine with a 0.05 - 0.1 max profit (based on 1% edge.)