I also have bitter sweet memories of CT's 400m recommendations. Sure they get you lean as hell, however, you really need to be on higher carbs and and lower reps in the weight room to off set that 'zombie-like' feeling.
I like running 200s and your notion of using a scheme of progression, at present I'm concentrating on 100s with a 1:2 work rest ratio x 10-15. From past experiences - and I hope someone might offer some insight on this - there appears to be a point where I hit a peak both in speed on the track and appearance, then really start to struggle with my recovery. At this stage I think there might be some sense in having a week of lower intensity sessions, say sprinting about 75-80% of max effort and just focus on technique and recovery.