If you could decide, what would you make the format for a debate between Presidential candidates look like?

If you wanted to have a real debate, you would choose a topic, then you would give the first speaker maybe a half hour, then the second speaker maybe an hour to rebut, then the first speaker a half hour to reply. Then in the next debate you would choose a different topic and you would reverse the order of the speakers. This is more like the way they did it in the Lincoln-Douglas debates, but unfortunately we have shorter attention spans now, and we cannot handle any more complexity than can be stated in a two minute answer.