That chart, made by SA, may have been accurate years ago for the Scientific Angler lines, but little else.
You can't get from diameters to line weights; there are too many variables.
Think about it, the difference in weight between silk, Nylon, and PVC is tremendous. Then, the silk or Nylon braided line would have been "oil finished". Since different manufacturers used different oil/varnish/resin mixes, there is another weight variable. Tight braid or loose braid?
The taper itself is the greatest factor to consider. Silk, and later Nylon, lines might have up to twelve feet of level line at the tip. Then the front taper might have been four feet or fifteen feet. If it was a WF, the belly might have been six feet or thirty feet. Then you have the "holding line", the back taper, and the running line... all variables.
So, how can HCH translate into a weight? It can't.
"You can't get there from here."