Humminbird-Greg can correct me where I wrong, but:
HB recordings are saved "raw data". That is why you can change Hummviewer viewing settings.
I do recordings on my 1197cSI(10" @ 800x600) and probably can see things better in HV also. Because my viewing laptop screen in 17" @ 1920x1080 resolution. And I can leisurely study the sonar history back and forth at will.
Best sonar is 2-4mph with chart-speed the same, straight-line on a calm day.
When fish hunting and detailed viewing, my SI range is normally 3-times depth or 40-60ft.
Mostly I use HV to find, study and mark structures. I will take a recording on a submerged bridge or pond dam, then use HV to waypoint the bridge-ends for example.