A lot more progress has been made on the deck:

Click on Image to EnlargeRecall, at left, the planned modifications to deck (bottom); where the red-outlined features were to be removed, and green-outlined ones added.
One type of feature - (inaccurately) high-relief, starburst patterns around the base of the forward capstan and deck gun, on the Nichimo mold (right) - had already removed. In fact, on the real thing, these radial patterns (of nonskid strips) were among the
least prominent features, on the real thing:
Click on Image to EnlargeAgain from a clip in the Victory at Sea disc II, Episode 7;
Killers to the Kill, the above pic shows the foredeck of a Type IX u-boat with features identical, as far as I can tell, to those on U-505, as captured - in fact, the movie could well have been shot from U-505 herself. In any case, note how delicate is the radial non-skid stripping around the capstan, compared to the deck planking, grating, etc. At a distance, these star-like patterns would practically disappear - and accordingly, that's exactly what I made happen to them, on the build.
I also relocated another, very prominent feature, which I had positioned incorrectly: a large, rectangular depression - perhaps a seawater chest intake, or recessed housing of some sort - right in the middle of the foredeck:
Click on Image to EnlargeIn this (part of a) mosaic I am putting together from another Victory at Sea clip, from the same episode as above, note the square hole in U-505's deck, just aft of the boarding party.
None of the reference pics reveal what lies in the bottom of this rectangular well; I guessed it was a grating, and outfitted it accordingly:
Click on Image to EnlargeAlready slightly out-of-date, this pic shows most of the corrected/added features on the foredeck. Note, in addition to the rectangular well (center), I have also added an open hatch, forward (left), and sculpted further detailing into the conning tower (right).
The latter has received yet another "pass" of adjustment/refinement:
Click on Image to EnlargeThe port side of the conning tower (left) finally has the precise shape and detail which are accurate, as best I can determine. Some confusion about the width of the upper wintergarten deck was also resolved, with the (re-)addition of plasticard (white), as shown. Just a few details have yet to be added to the starbaord side (right).
Again, the above pics are already out of date; this build has become much more involved than originally planned (surprise, surprise!

), and I should be able to post pics showing further progress, already made, hopefully by the end of this weekend.
Cheers,
-Matty