I appreciate your sharing this. A couple of years ago, I got interested in whether there might be any commonalities among elite training programs. There always seemed to be quite different approaches to training. In looking at lots of training schedules, I found that a total of 3 hours/day was very common and that was usually split into 2 workouts, usually early AM and PM. The details varied widely but 3 hours/day in 2 runs was the norm whether it was Igloi or the Kenyans.
Lately, I've been reading Dr. Maffetones book "In Fitness and in Health". His method is close to yours. Here is a link to his latest book which I have ordered:
http://www.amazon.com/Training-Endurance-Philip-Maffetone/dp/0964206277/ref=pd_rhf_p_t_3
His formula for your MAXIMUM (not average) aerobic HR is 180 minus your age, adjusted slightly for age, injury, etc. Mine would be 115 (180-65 = 115 BPM). For me, 115 BPM is about 64% of max. HR. I've been running at close to this level since Aug. 1. Its hard to run that slowly but I've noticed that my HR is coming down at progressively faster speeds during my 1 hour runs. I never would have been able to run that slowly without the HR monitor.
The program seems to be working very well for the first 6 weeks that I've tried it. I've been running an extra 5 mins./run for the past 2 weeks, making my 2 daily runs 65 mins. each. I'm going to keep gradually adding 5 mins. per run until I get to the point where I can do two 90 min. runs/day at a 60-65% max. HR level. Rarely, I need to walk to get back to 60-65%. After I get to 90 mins./day, I might incorporate some short wind sprints while still keeping it aerobic and run some 5K races for anaerobic work.
I really have to bury my ego because a lot of very slow looking people are flashing by me during my 60% max. runs but I'm sure I'm on the right track.
This article concerns PF which I have but it might also apply to your knee problem as well.
http://footloose.runnersworld.com/2009/04/to-prevent-leg-injuries-look-to-the-hips-not-the-feet.html
Again, thanks for sharing your knowledge and I'll look for your future posts.