Currently, the two casinos in question have a good reputation, which makes me think that they are reliable when it comes to handling larger amounts of money. However, if I were in your position, I would suggest using multiple bookies to place larger bets, in order to reduce the risk of any unexpected events, since hacking is quite common these days. I strongly advise against betting more than you can afford to lose. Trust me, it's not worth the risk. I know that sometimes you may feel confident about a bet, but in the end, the team you bet on may lose.