I'm looking to get a roof mounted 10" monitor and 2 7" headrest monitors, and possibly a head unit flip out 7" monitor. Are all monitors compatible with each other? How do you actually mount a monitor to the ceiling, need to weld? I may just start with a 10" roof monitor but defineately want to make sure its compatable with the others. I've seen some for under $100 and others for a lot higher. Whats the difference? TFT screen the way to go?