Thanks, Ben and Rick!
Argentine writer Jorge Luis Borges wrote a story called "The Garden of Forking Paths", the title of which pretty much sums up my experiences with the cockpit in my Nieuport project. I recently found two photos (rare as hen's teeth!) of the interior of the only surviving N.11, which now hangs from the ceiling at Le Bourget, and have been using them as guidance in my interior detailing. But as I've studied them, some perplexing things have emerged:

Most importantly, the seat is
not the "short seat" visible in most of the scarce photographs of N.11 interiors—many of which are, in fact, of Italian-built Macchi Ni 11000s—but the taller seat that I started building when I started out. And not only that, but it has the tubular cross-brace that supported the front edge of the seat, as is seen in photos of the N.17:

It presents an interesting quandary. On the one hand there's a number of photos of Nieuport 11 (or Nieuport-Macchi) interiors, showing the box-type mount and the short seat. But then there's the evidence presented by the sole remaining
French-built N.11 at the Museé de l'Air, showing what seems to be the later tall seat and stamped steel mounting arrangement of the N.17 (the cross-brace at the front edge of the seat would be unnecessary if it was sitting on the wooden box).
So here's the mystery; was the tall seat/steel mount developed at a late stage of N.11 production, and then carried forward on the N.16 and then the N.17? If so, that would explain their presence in the Le Bourget example. Or did the restoration team simply put in a seat/mount from an N.17? It seems unlikely that one of the most prestegious air museums in the world would make a goof like that.
I used to study medieval history, and learned early on to always go with your primary sources—the closer a document is to the events it relates, the more reliable it generally is. So who do you trust in this case, the photos, or the real aeroplane...?
Curiouser and curiouser, as Alice said.
I think I'll take a break and work on the motor for a while :-/
Dutch