I really have to comment on your explanation about notching. Notching removes excess fabric on convex (outward) curves on enclosed edges. It does not create space! It makes it so the excess doesn't overlap itself and make ugly bumps in between the layers. When the outward curve is turned back on itself ( as on an enclosed edge, as pictured) the length of the raw edge is longer than the space it has to fit in, so notching removes the excess length and lets the edge fit into the new, shorter space.

Notches need to be wide enough only to take out the excess - no larger. In other words, the edges of the notch need to meet each other when the edge is right side out. If made too wide the seam allowance changes from 4 layers to 2 layers and back again to 4- very uneven and ugly.

I've taught sewing for over 30 years and have read Threads for many years. This is not your best article.