In fog I run my main screen as radar, not worried about engine info as I am focused on what’s ahead of me. My second screen is gps as I find I am always turning right for some reason.
Having just radar to focus on targets on one screen saved me a collision this year as the targets are small and focusing on their movements is critical. Was 10 miles off shore and saw a target moving and getting close. I stopped and a trophy screamed by in the fog. He did not have radar.
I run a 9” as my main in dash screen. Normally for engine data while running and a second 12” for gps with just depths showing. Or split when looking for structure