That 20 in the bottom pic is absolutely beautiful! Love the hull color, although the Forrest Green they offered with the TM package was always one of my favorites.
A tower is the way to go. Just think about running your upper station rigging as you guys design it. What kind of controls are you going to go with? I believe Yamaha's 704 box can be used in dual station apps, but any others and you have to go with Morse dual levers or electronic ($$$$$).