30 bitcoin seems to be a great starting budget. Remember you need to reserve at least 10 bitcoin for the house. With 20 bitcoins left (14k) you should be able to build and secure a gambling site and have some marketing budget for the promotion.
Lol, a 10 BTC bankroll would = ~0.10
BTC max win, its not nearly large enough for players. Casinos make next to nothing from dust/little players, all of the profit lies in the larger players.
In my (biased) opinion, your best bet would be to build off of MoneyPot.
In my (unbiased) opinion, you shouldn't try and build this alone with your current budget (30
BTC), as you will have an extremely hard time getting players. Especially people who like to martingale due to the low max win (meaning reduced chances to double down).