The price list has a 'second slave screen only' (3400MFD) option and I wonder if the slave screen can be used as a third screen (in the back seat) because a 3400EF & 3400EM have already been installed in the front. Will all information (SV, MAP, WEather) be available on that screen?

Also, is the slave screen only depth much thinner or the same as the other units?