My week of experimentation is finally complete.

What I've learned:

The temporal luma variations (blown-out blacks and whites at scene changes) are definitely a part of the VHS. I must have failed to notice this defect on my 10" CRT TV.
The Panasonic DMR-ES10 stabilizes the horizontal jitter very well and slightly improves the big ugly curve on the lefthand side of the picture.
Using the Panasonic DMR-ES10 in passthrough mode is preferable to using it in record mode, as the latter suffers from too many MPEG-2 artifacts.

Plan of action:

I'll be doing five captures, at the rate of one capture per night, starting tomorrow evening.
I plan to use g-force's median-of-five (a.k.a., Median2) function on the five captures.
I'll have to capture the audio separately and sync it manually.

Goodnight!