I wanted a more relaxing project where every dimension was not critical.
I took enough pics. so a full explanation should not be necessary
Step 1: Find an old coat
You can see the arm pit becomes the half circle that forms the jaw area, I also stiched in the buttons and attached parts from the front opening to get the dimension I wanted, plus it looks more finished.
Those of you who sew don't laugh, I did it all inside out to hide the messy part of the seams.