The Hangar 9 Twin Otter is a scale model of the one used by the Air Force Academy's parachute jump team in Colorado Springs.  This model is powered by twin Saito 48's.  A TwinSynch is used to match the engine RPM's to each other.  I use custom made plug in wing electrical connections.  This makes it easy with so many wires in each wing (3 servos, on board glow, twinsynch rpm).  This way, when each wing is attached, all electrical connections are made, no worrying about connecting the correct leads.