I never understood why you would want to adjust your side mirrors to see behind you, that's what the one on the windshield is for. So I have been adjusting my mirrors per that video for as long as I can remember. Even with the side mirrors adjusted that way, I can still see behind me enough to make due if my rearview mirror is obstructed due to a load or a trailer.
2014 Jay Flight 28 BHBE
2015 RAM 2500 6.4L HEMI, Tradesman 4x4, 3.73
Blue Ox SwayPro (BXW 1503)
Upgraded from an REI internal frame backpack and a Eureka 1/2 dome tent!