Setting Player Data on PostLogin?

I’m currently working on getting a simple multiplayer system set up. I can host and join a game no problem, and the movement replicates fine. Now I’m working on getting players to have their names above their heads.

When hosting or joining, I ask for a username and save that in my GameInstance so it persists between levels.

Now I’d like to be able to have each client tell the server what it’s name should be. I have a gamemode blueprint created for my actual gameplay map, and I can successfully get the PostLogin event to fire. What I can’t figure out is where to put my RPC’s and from where to call them. The PostLogin event has a Player parameter, which I can cast to my “BattlePlayerController”, but how can I ask the client to send me his username? I’ve tried doing both multicast and client RPCs but I can’t get them to ever execute on the client.

Hit and run link, but this thread seems to have some info that is useful: