If you were planing on baking maps in substance painter, would you use the same unwrap approach for the wooden planks? Until now I thought that one must mark every 90 degree angle edge as seam. So that with the plank for example you would have 4 uv islands at the end.
Hope this makes sense.
I can't speak for Kent since I don't know this project as well, but I would imagine it's the same approach. More islands = more texture space wasted to padding, so fewer is generally better. The only time you NEED to mark every sharp edge as a seam is if you're baking normals and want the sharp edges to appear rounded.