You need to get your hands on betterbets.io because they are a great BTC casino (especially known for their super fast dice rolls and amazing plinko ) however they have no BlackJack .

If you are looking for BTC casino with BlackJack then you can possibly try bitcoinrush.io as they have BlackJack .

Just for references because your thread is about strategy so I would suggest to follow up this strategy

http://wizardofodds.com/games/blackjack/strategy/calculator/

This is as references to calculate the house edge of the house because each house has a different BlackJack rules that might differ the edge

http://wizardofodds.com/games/blackjack/calculator/