I followed the guide, and it does work... basically. I found that when I tried to run it on my 1440p monitor, it wouldn't fill up the entire screen no matter what setting I used. However, I was able to get it to fill the screen using my 1080p TV instead.
Also, you made a mistake: you said to put the shader fix in "/Game Folder/disk0". Actually, it's supposed to go in /Game folder/disk0/rom