I agree, I don't even worry with UV's on my blockouts, I just use a worldspace shader that applies a checkered material to all of my faces, and I tint the vertical faces of another color, just to make the floor look a little bit diferent.
This is very similar to what I use: https://forums.unrealengine.com/community/community-content-tools-and-tutorials/6142-auto-uv-color-material-for-block-outs-download-available