Time to tell of my goofs.  After all the effort at making sure the foundation plate for the upper superstructure was perfectly level, I flipped the model right-side up and added the canyon walls, so-to-speak, connecting the plate to the upper hull.  And I totally missed the fact that when the model was upright, the upper hull would SAG!
Fortunately, correcting that only required an hour or two.  The photo below shows how I cut the walls free at their top portions, flipped her upside down, then added some quarter-inch strips of styrene to maintain the proper gap once the upper hull was truly flat again.  I'd already added some detailing on those wall segments, and most of it wasn't affected by the increased spacing.  Also note the markings for where the lower hull will overlay the upper.  It helps with envisioning how far the detailing will have to go.

Detail section of an area below the beaver tail.  This is viewed up-side down from how it will be mounted.  An early effort at thinking INSIDE the box. It took some effort trying the keep the levels properly horizontal, but it was good practice.

These are a couple of segments for the arrowhead-shaped cutout on the ventral hull.  As I was working on them the detailing became more fine that what I'd already completed and glued in place for the waist.  It took a couple of days of comparing this with what I'd done before I resolved to re-do the waist.

So that's what this photo is; restarting the waist paneling.  This shows the five panels, each about 7 or 8 millimeters wide, with the detailing starting to grow.  As a product endorsement (for which I am not compensated,) the grid pad underneath is excellent for fine work like this. However, it reacts to standard liquid styrene glues, so pieces can get fixed to it if proper care is not taken.  Notice how the grid lines are almost gone in the upper left section?  That was due to a glue spill.

The waist paneling can be mind-numbing at times, so I decided to work on other areas too.  This is (what I call) superstructure section 3.  Sorry for putting it on white paper.  I'll find something to show better contrast next time.  Anyway, here it is with partial detailing.

And here it is assembled.  Detailing is about at 30%, I guess.

Same section, another view.  I've been able to find online some very nice photos of the original filming model to use for reference.  However, there's one area that I've not been able to find photos for, and that's the nose.  So this is a request for help; 
ANYONE who can find photos, please let me know the web page.  I'm not asking for views of other commercially available models, since there's too much variety.  Any photos of the nose, of the front 2 feet or so would be greatly appreciated.  I have nothing to offer as a reward.  I'm just asking for help.

As a final note, I've decided on a name for her.  It had to be something ominous, something with an edge, like how the British name their warships, so I decided to call her "Conquestor."
My daughter suggested "Baby-Muncher."  Maybe Palpatine would have liked that, you think? He was kinda freaky that way.