I admire your tenacity -
Going back to my original posts - understand that Boeing (and it could be any manufacturer) may have some limited historical technical data, and even though it seems like good PR to maintain and share that data, at the end of the day the folks up the food chain see such activities as unnecessary overhead and it cuts into their bottom line. Many of the people running these companies do not share the passion for aviation as we do. The only reason why Lockheed maintained a library at Burbank during the 1980s was because it contained a lot of technical information that was used by active employees before the internet. All the historical stuff was just there for the ride as it was easy to maintain during that time.
Hope this explains a few things.
BTW - in some situations the customer (USAF or USN) may ultimately own the rights to this type of data.
Again, good luck!