OK, I'm finally going to replace my Helix 5 with an new chart plotter and side vue sonar. I want to have a display at the helm and a second on the front end. I want to be able to add waypoints at either location.

I also have a transducer on my trolling motor that could be part of the same setup, or an independent unit.

So, how do I link two units to act as one?

Any recommendations on brand and features are appreciated.