Ahh, the wisdom of experience! Isn't it amazing how much we learn from our mistakes?
So much of what you described in your article relates to my own MYOG pack building experiences.
I started out using the pattern and instructions from Jay's article. It was a very good place to start. It had a "nuts and bolts" air about it with plenty of pictures to explain to a visually oriented person like me what the text was telling me to do.
Your article shows and tells why we do things a certain way to make our "SUL pack systems" work. We not only have to make choices of materials for our packs but we have to make the proper choices of what to put into our packs. As your example shows a well thought out and constructed pack could suffer greatly in performance from the use of a rolled sleeping pad that has been trimmed, shaped and/or is too thin and flexible.
Measure your torso twice and cut your material once! ;-)
Thank you Luke for the very informative article. I'll be saving it for future reference. It is a great example of not just how but why we do what we do in a MYOG pack.
Thanks for taking the time to sit down and write this article for the rest of us to enjoy and be educated at the same time.