For the plans I found an almost 'ready made' solution, which is the 'cut and stick' paper plane models by Fiddlers Green:
http://www.fiddlersgreen.net/As luck would have it, they have the civilian Sopwith Tabloid floatplane that won the 1914 Schneider Trophy race, which is especially useful for sizing the wings and the fuselage of my proposed Sopwith Tabloid scout in 1914 British service.
Having downloaded the pdf plans, I resized them to 1/56 (a simple matter of printing the pdf at 100%, measuring the distance between the wings, then reprinting the PDF at the correctly scaled percentage).
I have ended up with drawings that have a wing tip-to-tip of approx 140mm versus the actual scaled at approx 139mm.
My plane won't be made from paper: I anticipate a mix of plasticard, wood, metal, wire etc though much of the materials and process will be made up as I go along.
First stage was to stick plans of the main parts to 1.5mm plasticard:

I used pritt-stick as the adhesive and so after it has set and the detail has been scribed through the paper I can wash/scrub the paper/glue away.