3 External Sunvisor Questions

[Tod59]

Hey Guys-

The wife and I like the look of an external sun visor which mounts to the cab above the windshield. I posted a few pictures from 2 different companies:

Questions:
#1. Have any of you installed one of these on your truck and if so, how is the visor mounted? I can't find any assembly instructions online.
#2. Are holes required to be drilled on the outside of the cab?
#3. Or, does the visor somehow mount to the rubber around the window in the channel?
#4. If you mounted one of these visors....any regrets?

Any other advice will be greatly appreciated.

Thanks
Tod & Nancy

http://www.tuckersparts.com/Sun-Viso...-COV-5542.html

http://www.brotherstrucks.com/prodin...number=WSV5559