the crews of those turrets opened them to visually sight the target and individually fire them after the central fire control was disabled

Foolestroupe, while I haven't heard that, I see no reason to doubt your point; that's one of the reasons why even the archaeological evidence is not necessarily the final word in such matters.

As none of us was there (as Charley reminds us), I suspect there'd be only two sources that could verify such a point. The primary one would be eyewitness accounts of seeing the turret shields open; did this emerge from the German survivors' accounts. Charley's text may have mentioned it and there may be a reference to such an observation in Dettmer's coded report in the dictionary (I can't recall mention of it) although such an observation at 900 yards might be only made by someone with binoculars.

A secondary source might be documentation of such a practice being common procedure in the RAN on such ships as the Sydney, but I don't have those details either.

Which is why I think the naval historians have a way to go yet, even though my own primary connection is via the archaeology.

Cheers, Rowan