> in fact I pay as late as possible for the statement to arbitrage the interest difference between the 0% of the card for the first 30 days and the interest I can draw in the bank. I try to delay big purchases to the very beginning of the billing cycle as that's an extra month to earn interest before paying it.

No where near enough payoff for the mental gymnastics. I just pay the bill when I first get it and it is completely off my todo list.