I drive my truck every day, use the rectangular mirrors, even turned them the wrong way but you can really see what is behind you.....
started out with them up:
http://kieth.smugmug.com/Trucks/66-GMC/i-SjmHrpN
ended up with them out:
http://kieth.smugmug.com/Trucks/66-GMC/i-fz3HX3p
