Thanks for the feedback. I just raised the car and messed with the springs again. While the driver's side is the worst of the two, I should point out that both sides in the front make the same creaking lock to lock. That points to user error more than bad springs.

There is more like an inch of thread above my top nut on both sides, about 5-6 threads. Further out than yours, but my star nut is no where near the bottom of the strut shaft threads.

I got underneath and physically torqued the spring around. It does not appear to be broken loose in the bottom mount at this time, at least on the driver's side, which started making the noise again a day ago. I can get the beginnings of the creaking noise myself when I do torque the spring with my hands, although it will only rotate as much as the top bearing plate will allow; not much. The creaking sounds like it is coming from the top of the spring.

I feel like the only remaining thing I can do is completely remove the strut and stare at it blankly.

As a sanity check, the order of installation is as follows:

1. Bare front strut, push compressed spring down around shaft and seat bottom in strut seat.
2. Push on upper spring seat (IPD HD in my case), seat properly on spring top.
3. Push on bearing back plate, which fits snugly over the neck of the upper spring seat.
4. Screw on star nut down to an appropriate level.
5. Install large washer, ridged edge down.
6. Install final washer.
7. Decompress springs and put tension on the whole system.
8. Install entire strut assembly on car.

Did I somehow get the order of operations wrong?