Low Daily Installs: How badly will that affect?

I’ve made an Android Iconpack. So I have a massive Icon update in works, so I planned to add some sort of monetization into it. You might know, users tend to open an Iconpack only once, that is to apply. After that nobody reopens that app. One more thing that I’d like to mention is that currently the daily installs are just “350”. So after the major update I’m expecting about “700” daily installs. So I’m planning to use interstitial ads. First during opening and the second as soon as the user hits the apply button. So this way I could (I’m expecting) at least 1000 impressions.

Now 12% of my market is from U.S.A. rest all is vastly divided. So my question is how badly will this low daily installs affect? Also what Ad network you would suggest and how much (approximate) ecpm I would get?

In case you have a better idea for monetization than please tell.

B.T.W. It’s not possible for me to publish a new iconpack. I must give an update to the exisiting free app.