I really don't like these articles where the author provides a list of commands without actually understanding what some of them do. "sudo sync; sync" for instance. This is on par with copy-paste programming.
Some of his articles about the RPI have been pretty basic, but this one is actually pretty good, because it shows several methods. Just editing the config and rebooting didn't work for me the first time.
I don't necessarily think it's a bad thing. After all rPI is supposed to be educational, right?
Backing up config.txt does not make sense. "sync" alone might be sufficient.