Bicycles are supposed to do what? Bicyclist are just car drivers (some good, lots not so good) that have now regressed into a 14 year olds perspective on following the rules of the road because that is when a bike was their main wheels. They are also without the protection of a 3000 Lb vehicle.
As far mirrors go I don't use this method as I really need to know what is behind (no inside mirror) but I adjust them so I see a sliver of the my vehicle when I turn my head, and use a convex for blind spots. Works for me, and I have never had anyone die in the accidents I have been involved in this year
To some degree this is all for naught, I used to believe that all vehicles should have turn indicators on the side of the vehicle like most european cars have, but then I realized they are pretty useless because such a large part of the driving public don't use turn signals anyway. Doesn't matter how people set their mirrors if the don't use them.