This thread is fascinating reading. Having ran consistently for the past 2-years and seen little progress I may have come across this thread at the right time. I have a couple of HM and a 10k booked in this year but would like to get my 5k/Park Run down to the sub 18 level (pb 18:36) but idling around the 19:30 at present.
I won't be able to copy your schedule on a 1:1 basis so have laid out my plan below.
I can run 6 days a week, possibly 7. Given the importance of consistency of rTSS/load on a week to week basis I'll opt for 6 to avoid too much fluctuation on a weekly basis.
I plan to a schedule my week as follows (time in parenthesis).
E (40) - W (60) - E (40) - W (90) - E (40) - R - W (90)
Workouts initially will be 8x3, 4x6 and 3x12. The last two sessions will be in W (90). If I run a 5k on the Saturday I'll likely make the first W (90) an E (90 or 60) as a mini taper.
With the exception of the two W (90) sessions the other runs have to be juggled around lunchtime at work. If I'm in the office for optics I can really only commit 45 minutes at most for a run so the W (60) session would have to be cut short albeit it is only the non-workout element that is reduced. In such a scenario I would add the lost 15 minutes of easy running to one of the E (40) runs (when I'm not in the office). From a rTSS perspective the forecasted difference between E (40) + W (60) vs. E (55) + W (45) is only 2 points, so feels like it's within an acceptable range of tolerance.
The only pitfall I see is the potential for the W (90) sessions to generate fatigue which over time may require dropping a session as a refresh or cutting it back to just an hour. At the end of the day it is just running and trying to stay as consistent as possible is the most important thing and replacing a W with E run every now and then won't see my “legs fall off” or too dramatic a drop in CTL.