Well, I had to watch this video twice because I found myself so enamored with his gaming skills I didn't hear a word he said.

I came up with .7 radians which is, if I understand him correctly, 70 degrees. The automatic setting in AH is set at 100 so I'll give 70 a shot.
Also, it seems to me that Frankie was saying to reduce your game FOV to more closely match your actual vision (relative to your monitor) but lots of you are going the opposite way and going to extremely wide FOVs. In either case, it's an interesting experiment.