I realized that I never closed up this thread.
Instead of building up mileage and starting to double as the mileage got high, I started off doubling and gradually built up the mileage. I started a week after a poor showing in a marathon.
I doubled for 128 straight days. The harder and/or longer run was always in the morning. The shorter run was usually 3-4 easy miles, but sometimes (rarely) as short as a mile, as life intervened. Yes, it felt cheap, but whatevs. Three workouts a week. The third workout was either a long easy run or about a 10-12miler at MP (the second run on these days was always very short). The first week of the streak was 50 miles, this highest volume week was 90 miles (nearly 20mi longer than my previous weekly mileage PR), and my lowest was 38 (the week of my goal race, a half).
Along the way, I ran two 5k PRs (without training for it) and PRd my half (by only :30, but on a much harder course). I also stayed healthy throughout the process. Tired, but healthy.
By the end, it got to be a real chore, and I finally just didn't make it happen during a two-day meet one weekend. Streak broken.
Takeaways:
Lost a lot of weight, in a good way. Probably something with keeping metabolism up? I have definitely put some weight back on since I broke the streak, but I have also decreased mileage.
I felt like starting with doubles and THEN building up miles was unconventional, but I really liked the results (and I felt like I stayed healthier than my previous high-mileage phases). I would recommend this approach to anyone looking to try something new.