I’m just starting my trial and error setup of netplay. I have a RPi2 and i’m trying to get this to connect to a friends desktop to play across the country like you are indicating. At this point what I have learned is that you must both be using the same version of retroarch, emulator and rom. I’m messing with the client and Host end configs now and seeing how to make this work. If I figure this out or if you do please let me know.