You can use any CPM networks as long as you dont cross the maximum number of other networks you can use along with adsense. I really want to know that is it 3 more ad networks I can use along with google or only 2 more and 3 includes adsense.
Sorry but I never heard about this limit on number of ad networks. To my knowledge, these ad networks are not so keen about sites having non-US traffic. Also they require good traffic. So chance is that you may not get accepted if your site does not have too many US visitors. Of course you can apply and try.