I use a 998cSI with GPS puck on the bow and 1197cSI at the console with GPS located on transom. This places the GPS pucks close to their transducers in normal operations.
They are connected via Ethernet and can share waypoints, GPS pucks and transducers.
When navigating a crooked path sometimes I have switched the 998 bow unit to read from the rear GPS and transducer.
Note: Waypoints are shareable, but HB tracks are not shareable. I maintain all my waypoints on the 1197 console and they are visible at the bow.