Why do this the hard way? Just write to the players HUD. Spawn an inventory item on the player, have that write with PostRender, then destroy itself with a short lifespan. You can have the message feed from a server ini file that you can change at will.
Doing it your way makes your server have (in essence) pop-ups. *No one* likes those. People join to play, not to immediately need to click off some message window so they can get to what they came for. Think of how that makes you feel when you mobile into some website that does this.
"You damn kids, back in my time we made the items, maps and games ourselves with an unwieldy engine using counter-intuitive crash-prone tools and we liked it so much we built communities around this which nowadays look like cults because they're quasi-parallel societies based on the same old games." -Hellkeeper