Marines keep red for all enlisted, regardless of grade.
I have never seen placards on a POV. The 5x8" does sound about the right size for the ones we'll put in official vehicles for general officers when they're riding in them.
I've never seen official rank insignia lower than colonel on any vehicle in the Marine Corps. My guess is because reserved spots start at colonel and above. I've seen plenty of the unofficial ones you can buy at the exchange of all ranks. Unless you're a 1stSgt + or a col + I don't see the point of that. The 1stLt or corporal aren't getting the spot by the door on account of their ranks, and just look cheesy doing it. Maybe the culture is a little different in the other services.
I have never seen placards on a POV. The 5x8" does sound about the right size for the ones we'll put in official vehicles for general officers when they're riding in them.
I've never seen official rank insignia lower than colonel on any vehicle in the Marine Corps. My guess is because reserved spots start at colonel and above. I've seen plenty of the unofficial ones you can buy at the exchange of all ranks. Unless you're a 1stSgt + or a col + I don't see the point of that. The 1stLt or corporal aren't getting the spot by the door on account of their ranks, and just look cheesy doing it. Maybe the culture is a little different in the other services.