This may be one of the MOST important pieces of sewing/fitting knowledge out there. I had never seen this demonstration before until Cynthia Guffey showed it to us at ETA. I knew about the Upper Back issue and had done the Palmer/Pletsch method many times, but I never knew exactly HOW TO MEASURE to see how much correction you need.
There are several videos here, but they are short.
This one shows you how to measure the actual curve of your back:
The next one shows you how to correct your PAPER pattern for the measurement you now have:
The following video shows the paper pattern after the adjustment against Phylly's back.
NOTE: Correction to following video: The garment would pull to your BACK -- not your FRONT -- without this correction. I got it wrong near the end of the video.
ALSO: Phylly didn't get pics of the paper pattern pinned together. She went right to making a muslin which you can see below.
Here are some pictures Phylly emailed to me this morning showing me the MUSLIN made up with the round back correction in the back. It is a bit snug at her waist, but the back covers her high round very nicely and the top will NOT pull to the back trying to make room for it.