I have read this thread with interest and I have to say that AtagahiKC you are definitely embarking on a long journey. I'm not saying that you can't do it, but your ambitions to provide your fellows with a custom-fit pattern may be more complicated than it's worth for the average person. Think about your own words "i'm not naive, i know what i'm getting into". This is not something for the average person, but an in-depth study of a wonderful art. How are you going to translate that body of knowledge into something an average person can understand and use? If there was an easy way, it would already have been done. Seriously.

I would also update your references to:
(although the Classic Tailoring Techiniques is good. Some of my refs are geared with women's clothing in mind, however they are still very good starts)

Fitting & Pattern Alteration: A Multi-Method Approach
by Liechty, Pottberg, Rasband

The Sew/Fit Manual (Book)
By Ruth Oblander and Joan Anderson

MAKE YOUR OWN PATTERNS
by Rene Bergh

Tailoring: The Classic Guide to Sewing the Perfect Jacket
Singer Sewing Reference Library by Creative Publishing
(real and up close photos of the sewing method)

Also, have a look at:
Real Fit for Real People
Pati Palmer; Marta Alto & Jeannette Schilling
-definitely geared for women, but it shows you the technique of taking a commercial pattern and altering it to fit by fitting the tissue to the body first

I'm thinking that you should lean in the Real Fit direction by learning how to fit a Real Man from a commercial pattern template. Check out the McCalls Palmer/Pletsch patterns and you'll see extremely detailed instructions and pattern markings that are enormously helpful in fitting the commercial pattern. You may find these helpful in translating fit to the average person.

Paper: Try medical table paper liner on 200yd rolls. I get mine ($8) from a medical supply store, but some get it direct from their doctor.

Don't get me wrong. What you are trying to do is a wonderful thing. Definitely a needed thing. Don't hesitate to contact me if you need some advice.