Offshore, or onshore jj?
A good guestimate that Ive come up with, using a little bit of bj/poker bankroll strategy, is around 100-250 times the largest wager you are willing to accept. Ie, 1000$ = 100,000 or more bankroll, to ensure you dont go broke, but these are really out of the air numbers, based on what Ive read here, and other places. The more of your players, betting the max, often, the larger the roll would have to be.