I absolutely love the art in this project, but as mentioned by many others, it doesn't work out of the box. After comparing its assets to competitors' that work well in hex kit, I found a way to hack this pack into working again.
I don't recommend it unless you're comfortable with the command line.
In hopes that Zeshio will try it out and submit an official fix for the pack, here's what I did:
1. Edit settings.yml - change padding to 12.8
2. Install ImageMagick
3. Using command line / powershell, navigate to the pixel hex directory and run this:
magick mogrify -bordercolor transparent -border 6x12 -chop 0x12+0+0 'IMAGE DIRECTORY\*.png'
4. Repeat for each directory containing images (E.g. "01 Grass"). In Pixel Hex 2 you'll need to include each nested subdirectory as well... It's a pain.
The ImageMagick script adds a transparent border to the sides and bottom of all the .png files in the given directory, which centers the image and gives a bit of padding.