[drzen]

1/ I just can't see how that can be a HUGE leak. He could well be pushing very tight there.
2/ I am learning to stop doing that. He is mostly calling and you're mostly flipping.
3/ This is one of those situations where I would feel confident you were bluffing (I'd tend to think someone who bet this much didn't want a call and most aces bet the flop) and whether I called would depend what I had. With any half-decent bluffcatcher, I'm calling. So is it worth your risking so many chips? Dunno. It would be player dependent.
4/ This is nothing like "standard". It would depend on the other player. I tend not to believe they have a flush, because they rarely do. But with your stack, and another card to come, I'd probably let it go.