Well, whatever winning the gamblers get, he should be happy with it. A $1700 win from just 20 cents is undoubtedly a huge win. He had nothing to lose in this bet but he won a good amount of money. I don't think he should regret not putting more money in, like $10, because he could have won 10 times the amount.
Actually, he would have won 50 times more had the stake been $10, not 10 times more. 10 is 50 times larger than 0.20. But that also equals to much more risk, and we have no idea how long he was playing before he hit that amazing multiplier. Imagine spinning the reels 100 times at $10 per spin. You need guts and deep pockets to do that regularly. They could be a possibility that if he had bet a large amount, he would have lost instead of winning, so better to be happy with the win and enjoy the moment. 
That's always a dilemma in gambling. If you win, you ask yourself, why didn't I stake more. If you lose and you lose big, you hit yourself in the head saying, why was I so stupid to bet that much!