All of that brick corner work turned out to be kind of pointless in the grand scheme of things. It ended up being impractical for modular use because it only worked for certain width areas. At least it was a good learning experience. Here’s a test window texture.
I added some details to my low poly model. It seems to have helped the corners, but they are still not without problems. I think the seams that are visible now are due to separations in the uv shells.