How do you come up with whitelists on native?

Hello, everyone! 🙂

So, I have ran a couple of native offers on RevContent on tinnitus and solar energy. Both of these have some widget id’s that were either profitable or that at least had revenue.

Now, question.

I was wondering how do you build your whitelists for widget id’s? Purely by testing? Can you buy those from someone? Something else?

I have bigger whitelist on tinnitus related product on RevContent, and I’ve been thinking of maybe creating a new campaign only to the whitelisted ...