@neologist,
The link diameter is outside.
The link shape is oval - 8 inches across straight parts, 6 inches in length straight parts, radius of curved ends 4 inches.
The diameter is 3/4 inches.
Maybe that will be of help.
Note: I can read the diagram from the link on my pc and tablet. The little magnifying glass with the "plus" sign at the bottom of the page will make the image bigger.
Also, the title of problem should be Length, Weight not Width.