I usually like 12-14, but yeah, it definitely depends on peak mileage. Every week of the taper should slice out a percentage of the mileage, so your week-out run will be different if you're peaking at 60 mpw than if you're peaking at 100.
Finally getting around to sharing some photos/thoughts from this run. Still didn’t really capture the brain of the run.
Highly recommend it in general, but it truly felt at times like I had the entire city to myself running this early.