In essence the process points you just named are correct. What you need to track in the early stages is the high CTR ad block. Once you have tracked that one down you can them make the ads in your site more competitive by removing the low performing ad blocks and you will not really have to hope, you will just have to target the ads and the right advertisers will have the exposure for which they paid.

Thank you for taking your time to comment

Did I got it right?
“if I want high paying ands, I need few ad blocks” just 1

process:
1) fill up the page with ad blogs
2) wait and know which block has higher CTR
3) delete all the other ad blocks
4) hopefully the high big ads will appear in the high CTR block, because if there’s few space, Adsense chooses to display high bid ads first.

right?

(I just commented because I felt so sorry reading the first lines of the article

BTW: this page is the 3rd result when googling for: “use adsense earnings to pay adwords cost”

http://www.google.com/search?hl=en&q=use+adsense+earnings+to+pay+adwords+cost&btnG=Google+Search

congratulations