Rudi,

A great piece of information for a common challenge, especially for vintage IGH fans. I've puzzled this in the past but never took it far enough to come up with a solution. My helmet's off to you for doing so! I've saved it on the computer for future use.

My only suggestion would be to add the directions you used to begin this thread to the PDF and to specify whether this is for a 3X or 4X pattern (or that it doesn't matter).