Ian,
Thanks so much for posting the link to your SPAD build. When I was working on my MAC SPAD VII, and before I screwed up the upper wing, I was contemplating how to accomodate the double wires in such a small space. An old friend of mine on the World War One Modeling List (Crawford Neil I believe)did a beautiful job on his 1/72nd SPAD, and my goal was to equal his efforts. I'll be looking to your build thread in more detail later to learn from your efforts.
Ken,
I know there are at least a couple of folks on the above mentioned list (Shane Weir comes to mind) that built the Roden Felix and used mono-filament, etc. to rig it. If you can't get an satisfactory answer here, perhaps you can slide on over there. In all cases of this build the modelers have stated that using the mono to rig and provide tension helped with the strengthening of the wings, etc.
HTH!
Warren