I just got a take a look mirror & I have to say that I am still getting use to it, but may never get use to them. The mirror doesn't shake much and fits well to the visor with zip ties. I believe it may give you a larger field of vision if you can get it closer to your eye so check your visor to see how far back it comes.
FWIW, I feel that since I have to move my head around to get a good view of what is behind me that I still just turn to take a look behind me anyway. I also found out years ago when using 3D glasses on geographical maps that my eyes were farther apart than the average person giving me more peripheral vision which helps with looking over your shoulder.