I put mine in all three positions - left, right, and center.   
I machined brackets to mount the outer ones to the windshield frame.   There are some more shots of the bracket in my gallery.   I also put in convex lenses, which greatly improves the field of vision.  The lenses are available from 
Aardvark in Whittier, CA:   
http://www.talbotco.com/talbot_mirror.htm
I discovered these years ago at the Concorso Italiano - technically, they are for a 
Talbot, jr. mirror, rather than a 
Raydyot  - but they do fit in the housing, and make the mirrors much more useful. 
regards,
Jeff