I attempted this and it works like a charm. The only difference a rod makes is what level it is. Be sure to be right under the bridge's shadow. It is the one right after weather Institute.There's something wrong with the how to encounter Feebas guide.
I made it to Route 119 today and fished under the bridge the picture was showing, in daytime, and didn't get any Feebas, as it said. Still, it's not 100%.
Perhaps I'm using the wrong Rod (I only have the Old and Good ones right now), but still this is curious.