--Originally Posted 12/18/12--
Well, for the permanent attachment of the top casing I guess my good luck ran out, because it proved
'WAY more difficult than the earlier dry-fitting - I still don't know why. What I
did know for sure was that I was
not going to do it over again - so now to address its shortcomings, left in the aftermath. Most notably, a significant gap remaining along just about the full length of the hull joint:

Click on Image to EnlargeAs usual I filled the gap with superglue putty (left) - however thinking ahead, I had first laid down some masking ("resists") of of aluminum tape, wherever I didn't want any putty to remain. Particularly in notches (bottom) where the limber "holes" would meet the pressure hull. "Holes" in quotes as they were actually
arches, cut into the bottom edge of the casing plating (as opposed to true, isolated holes - which were also present, higher-up on the plating). After the putty bead was sanded flush with the casing, and down to the (tape also protecting the) pressure hull, the blocks of putty covering these tape strips were cut out (right), and all masking removed.
Viewed in just the bare plastic and translucent putty, the result looked perfect - too good to be true - and I gave it a quick overspray of Testors
Gloss Black:
Click on Image for FULL-RESMy first-discovered error being the choice of black - the second-worst color (behind white) for checking surfaces - this pic (at full-res) being the only really decent look at the results, overall. In which the cutouts (not yet the full arches, which will be taller) are clearly there, and the casing fairs smoothly to a (now lower) bottom edge (of approximately the thickness of the aluminum tape), against the pressure hull.
Attempts to photograph from either end, all insisted maddeningly on focusing at the same few notches, amidships:

Click on Image to EnlargeWhich I guess was just as well, since multiple segments both ahead and further aft (left, and right at right), were insufficiently filled and/or smoothed, particularly on the starboard side.
But in point of fact, even the "perfect" stretches of fairing - coincidentally, ideal for a Nautilus SSN-571 or similar, Skate-class nuke - are
not correct for an S-boat:
Click on Image to EnlargeTo be accurate, the top casing should came to a hard crease - with no gap whatsoever - at the joint with the pressure hull, and extend in narrow "foot-plates", flat against the pressure hull (again, proud by about the scale thickness of the aluminum tape), outboard from there. Only now did I realize the putty should have been applied in
two runs: first extending the casing downward (with the pressure hull masked), and next forming the foot-plates (with casing masked) - and comprehensive smoothing/finishing, in between.
At this point, to fix the above, ideally I'd simply use a corner-type knife blade to carefully scrape/sculpt the crease right into the putty - which, indeed does comprise a soft, workable plastic - however it can also be
crumbly (not to mention sometimes pop right off) when subject to such focused pressure, expecially in small areas. Then again on the plus side: the thick, goopy Testors paint continues to cure - hopefully to further bind the putty, for (at least) somewhat better integrity.
In any case, I haven't (yet) thought of any better solution(s) - other than to scrape/pop everything back off, and redo the entire casing (the right way), after all. Not at all my preferrence, at this point.
So I will probably just wait a few more days, and give the above idea a try.
Cheers,
-Matty