This Two Very Good Facility I like much for google adsense , i want to help the users who always asking the question about how to earn more money from there adsense and where to put ads to earn more and etc . Here is your solution , create google custom channel and track any particular adunit ( for example say your are creating 720*90 leader board) and in 2 days some few clicks and instead of this leader board you will put Large rectangle and your clicks are increased , so this is the genuine way to optimize your ads, search in google for custom channel adsense. and URL Channel gives you the total ad clicked for particular URL. Hope this notes will help you , pm me what are you thinking about this tip.