When I worked for Sperry Marine, we developed something called "SmartShip", put a fully integrated control system on an Aegis Cruiser. The skipper of the ship could navigate from anywhere on the 550' ship with a wireless laptop, could even start/stop engines, generators, etc. Integrated the Electrical/Propulsion/Navigation/DC systems. Pretty neat. We put it on the cruiser in 16 weeks. The Navy took the program over and it took them over a year to do the next one and it didn't work as well....Oh well... :disgust
I fould that with the overlay function (on a 27" color touch screen no less) was a great thing to help you resolve what radar contacts really were! Ships don't show up on a chart but land masses/marks, etc do. Also helps you learn what a radar return is!
Go for the overlay, you'll like it. More screens are good too, Bob's right!
Charlie