Here's the write-up on normal maps that I mentioned in the video:
https://www.artstation.com/blogs/typh...

The part I talk about in the video is on part 2 of that document, under the section called "Bake Seams"

Also, I realized after recording that I never went back to the Harden/Soften edge tool. All it does is automatically harden or soften edges based on an angle threshold, which you can set manually, or leave at the default 30 degrees.