My search did not pull up anything specific.
Tips, tricks, secrets? The best way to notch the corners for a squash?
You could pinch the cloth with your fingers to see where it lays up. The lines should still show after you pinch it.
In between your diagrams there is a good cut.
Straight in from the tail to the square tip, then 90 degrees out to the side. Cut the 0-90 using the weave as a guide.
Worked for me for years, and still works now.