OK, an update.
The drive mechanism has been repaired, and the top / clamshell now go up and down as they should. (Side note: Failure was due to a broken cable end which disabled the drive on the passenger side).
Now my attention shifts to getting both ends of the clamshell to sit flush to the rest of the car.
Reference photo:
Driver's side:
Compared to the passenger's side, which is pretty close:
In addition, the front "point" of the clamshell is also off on the driver's side. Here's the correct-looking passenger side:
While the driver's side looks to be shifted:
The situation now is that, looking at the underside of the clamshell and the linkage between the motors and the bracketry, I see no indication of adjustment capability. Certainly there must be some means to fine-tweak the fit of the clamshell, but I see nothing.
Any hints? (A Search of this Forum for this info came up empty - can I be the first person to have ever encountered this?)
Thanks - DM