Lately I really want to go deeper into slot games and others. Moreover, seeing the duelbit competition that is won by you very often, makes me curious about the strategy to win each game. I didn't have a good knowledge base in slots until I studied slowly in the thread the OP made. To my knowledge, playing in gambling is just pure luck and there is no winning strategy. and does it have to be big to win big bets too?
You have answered about your curiosity yourself, it is pure luck based game and luck is the only deciding factor but you can try to push your luck by keep playing as long as possible.
Your bet amount has nothing to do with your luck, but it is obvious that bigger bets will give you bigger wins but it requires you bigger bankroll to start.
If you want to beat him, you need to have bigger luck and maybe bigger bankroll or at least equal bankroll to his bankroll.