Do you want to get the another 1BTC fast or not?
If you want it fast, just All in it the first bet with 50% chance, of course its a HIGH RISK.
but if you want it with several bets, u can use your own strategy and feeling.
The thing is that betting everything at 50% is not really high risk.
If you use martingal with base 1k satoshis, (with 16 loses in a row you cant double again)
So you would need to win 100.000 bets so you would have to bet about 200.000 bets in total, now lets calculate the chances of loosing 16 times in a row on 50%, they are 0.0015% wich is 1 in 40.000. So every 40.000 bets you would go into a 16 lose streak (most likely) but you would need to do 200.000 bets so the chances increase so yeah