We don't really share traffic sources because that would cause to much competition for everyone. Plus no two people will ever have the same experience on a traffic source.
The best advice I can give is for you to reach out to the traffic source and ask for their top 5 countries by volume. Also make sure ask them how much of their traffic is from direct relationships. If they don't have many direct relationships then that means they're simply buying the traffic from someone else and jacking up the CPC. Finally make sure to ask them what kind of traffic they have, APP / Web and Categories. In some cases I even simply just ask the reps what's working best on their network.
If they don't give you what you need simply go above them until you find someone that can give you the answers you need . - Linkedin is always a great tool for this.