I figured this out years ago and have always adjusted my side-view mirrors thusly:
The Society of Automotive Engineers (SAE) published a paper in 1995 suggesting how outside mirrors could be adjusted to eliminate blind spots. The paper advocates adjusting the mirrors so far outward that the viewing angle of the side mirrors just overlaps that of the cabin’s rearview mirror. This can be disorienting for drivers used to seeing the flanks of their own car in the side mirrors. But when correctly positioned, the mirrors negate a car’s blind spots. This obviates the need to glance over your shoulder to safely change lanes as well as the need for an expensive blind-spot warning system.
Everything they say and show in that very short article, published 15 years after the 1995 SAE paper, is 100% true. Now it's almost 15 years after that article was written, do people still adjust their side mirrors in the (wrong) goofy way???