Hey Ck.
Both units can share the LSS-1. You just have to be aware where the puck is. The LSS-1 can be a communication hub using ethernet. Here is a link for some setups and tips. BBC Boards: Lowrance Help Topics, Contact info, Networking Diagrams Wapoint sharing with HDS models: Ethernet will share waypoints as well as NMEA 2000. But with the Ethernet you will have advanced or enhanced waypoint sharing and editing which means the two units will auto synch with each other once connected and turned on. No manual tranfers needed. This is a great feature. You can edit a waypoint on one unit and the changes are made to the other(s) automatically once they are turned on. Other units do not have to be on during waypoint creation. Once connected it will synchronize the other units.