What I was trying to say is that basing a site only on CPM returns isn't worth the trouble. Your site would have to get like 10K hits per day to be worthwhile, and if you're getting that much traffic, you're getting at least 50 clicks a day, so you may as well aim for the clicks and not the CPM.
I only use CPM programs to supplement sites I no longer promote/maintain or sites that underperform. I used to use it for brand new sites, while I got my clicks up, but the CPM program I use works best with a sliding banner ad, which kept repeat visitors down.