Getting a 2nd PS4 but a Pro this time, which one should be primary and which one should be the one with Ethernet cable and other with wifi

I'm getting the PS4 pro white version this Wednesday but a little confused on which one to be primary console....I have googled the question but still a little confused...should the new one (pro) be primary with Ethernet cable and the other one (PS4 slim) non primary with wifi or vice visa? I have my slim in the bedroom right now with Ethernet cable since router is in bedroom but putting it in living room when I get the Pro on wednesday.....I want the Pro in my bedroom and slim in the living room...how should I set it up guys..thank you very much for your feedback