O.K., I came home faster than expected.
I can't add more to the struts question besides, yes I would say too it was canvas and painted horizon blue on early Nieuports, silver doped from Nieuport 16 N1109 onwards (probabely the first Nieuport painted in silver dope according to Bernard Klaeylé and Marc Chassard).
Now my two cents on the "Wing question":
I Checked the references you mentioned.
WDF Special, Vol. 2:p. 31, pic. no- 64 is that famous squadron 1 picture that is published in many publications. The Serials are erased by the censor, but it has a date: 27 Dec 1917. The first plane in the row, marked with an "H" shows a dark lower wing (solid color? I can't see no traces of a camouflage demarcation - neither I can see other Nieuports with dark lower wings...)
WDF Special, Vol. 2, p. 40, pic. no. 91 is T O Clogston in a Nieuport from 111 Squadron. Undated picture, no serial. There's also a dark colored lower wing (at least part of it).
besides of the WDFs I consulted "Nieuports in RNAS, RFC and RAF Service", published by Cross and Cockade International in 2007 (sadly oop. today). It's really a valuable source when it comes to British flown Nieuports.
1 Squadron flew Nieuports 17, 23, 23bis, 24, 24bis and 27. Received Nieuport 17 in Jan 1917. The new Nieuports (24, 24bis, 27) were issued on 15 August 1917 and the squadron dropped their last Nieuport on 24 Jan 1918 in favor of Se 5a's.
Although the serials on the mentioned pic are erased, 1 Squadron surely flew the Ni 24/Ni 24bis B3607, B3608, B3609, B3612, B3613, B3614, B3617 and Nieuport 27 B3629.
On p. 130 the Nieuport marked with "H" is identified as a Nieuport 27 with the serial B3629. There's a color profile on p. 77 depicting this very plane with lower wings painted RED and red squadron/flight leader steams. The plane was flown by 2LT W W Rogers, 2Lt P Wilson and 2LT G B Moore (shown on the mentioned photo). On 17 Dec 1917 it overturned on landing (and was repaired? Probabely...).
There are many other color profiles in the book, several show Nieuports 24/24bis/27 in silver grey or French 5-color camouflage (introduced in October 1917).
111 Squadron flew in Egypt (not on the Western Front) and was equipped only with Nieuports 23/23bis. These were shipped unassembled, in parts and had to be reconstructed at Squadron level. They used them until Jan 1918. I quote P. 62: "There were never more than six or seven Nieuports on strength in 111 Squadron, of which half were always unserviceable." There are some color profiles of Nieuports from 111 Squadron as well, some equipped with camouflaged spare parts.
Given these informations I personally would say with quite few doubts that the dark lower wings were NO certain squadron marking but either camouflaged replacements or (B3629) painted in a color that was possibly red. The question is: If they used spare parts from other, camouflaged Nieuports, what camouflage color had these had? In the case of B3629 in my opinion much speaks for a solid color, so red would be a good choice, but PC 10 isn't impossible neither, because several British flown Nieuports 24/24bis/27 were repainted in PC 10 at the repair shops. Can't say anything about the 111 Squadron Nieuport besides that it should have been a Nieuport 23 or 23bis (contrary to the WDF that depicts it as "probabely a Nieuport 24bis"), probabely/maybe with a camouflaged lower wing (French 5 Color camouflage).
I of course cannot post these color profiles here due to copyright issues. But I can't see any problems in making a pic and email it to you, Tug, if you PM me your e-mail adress.
I hope that helps. Browsing through the book made me again wanting to build a Nieuport...
Best wishes
Borsos
