Tremendous postings!!! You have a wonderful ability of explaining human physiology in a very simple way.
I am a 36 yr old former collegiate 800/1500 guy who has been struggling with my running for the last 12+ years. I have always had great speed (still can run 400m in the low 50s), but always suffered outside those distances. I was one of those guys who went out hard and held on. Since 1990, I had tried several marathons but always suffered through them and always ended up walking.
Last year, I decided I needed to try something different (It took me long enough to figure out that what I was doing was not working). Fortunately, I found the answer. I have 2 friends that I have been running with on Saturdays for about 5 years. Both are strong runners, but not outstanding. However, both are very well read and very intelligent. They are real students of the sport of running and everything else they do. They have put together a 22 week (5 cycle) marathon plan that seems to mirror your previous posts. The results have been tremendous. 5 weeks ago I had a 38 minute PR in the marathon and finished feeling great. I have just this week started my training for Boston after a 5 week lay-off and my body has just bounced back. My speed is as good as it has been in the last 10 years and my running economy has just flourished. I will be very surprised if I don't take another chunk off my marathon time come April.
Keep posting and I may hit you with an email or 2 every now and then.