Replicating Aim Offset in First Person Example?

I’m building off of the first-person example for an arena shooter. Double-jumping and fully-automatic fire were easy enough to add and replicate, but I just can’t figure out how to get looking up and down to synchronize across clients. Base Aim Rotation doesn’t seem to be the culprit, since looking straight up and straight down have the camera’s world rotation max out at 70. Does the base look-up rate factor into the calculation? I can really mess with what the other clients see if I set the base look-up rate to 0, but I don’t know what to do with that knowledge.

How can I get how a player is aiming to replicate across a multiplayer session? I’m aiming for a BP-only solution, if at all possible.