Just to be exact: Area Mex + ALT queues up the Metal Extractor first, then surrounds it with 4 Solar / Wind / Tidal, if the building placement is not obstructed of course. Then the constructor goes to the next metal spot and repeats.
My intention with the method in my first post is to build all Metal Extractors first in an area, then surround all of them with power plants.
Area Mex + SHIFT also cancels the previously queued extractors:
1. Use Area Mex in an area -> queues up the extractors
2. Use Area Mex + SHIFT in an area containing the first either partially or fully -> all Metal Extractors in the intersection are cancelled.
