Hi Joe,
Are there any good magazines or books targeted specifically to the WWI model genre?
Start here:
Albatros Productions / Windsock Magazine and Datafiles. The datafiles are the go-to reference for most builders here.
WWI Aero is a great if sometimes eclectic resource.
Over the Front is the magazine of the League of WWI Aviation Historians.
Osprey has a number of useful titles, mostly unit histories and the like, but useful for research.
What, exactly, was used as the cloth covering? I would assume a sort if canvas or burlap.
Linen, a kind of canvas. Stretched over wood and/or metal structure and "doped" to make it taut and waterproof.
Was factory paint sprayed on, brushed on, or dyed into the fabric, or wood?
All of the above!, depending. Early on, both sides simply doped the linen with a clear nitro dope -- thus CDL or "Clear Doped Linen" as it is referred to today. After about mid-1916-ish(?) the British started finishing the upper surfaces of their aircraft in "PC-10" (Protective Coating #10) which was painted on. The exact color of which is the subject of endless, if mostly friendly, debate. French aircraft were variously finished in silver colored dope, tan dope or various camouflage patterns which seem to have been brushed on. Check your sources. The most variation was found in German aircraft, which varied considerably by manufacturer. Albatros fighters were delivered with varnished plywood fuselages and camouflaged wings and tail surfaces of several colors and patterns, which appear to have been sprayed most often. About mid-1917 the germans started using
Flugstoff, pre-printed camouflaged fabric with a geometric pattern that today is (somewhat erroneously) referred to as lozenge.
Was the rigging painted, bare metal that got rusty, or was it covered in oil/grease to protect it?
Generally nothing lasted long enough to get rusty, but in most cases the fittings would have been plated or painted to ward off corrosion.