I tried an experiment and extruded an area of nurbs circles to get the cable effect, unfortunately the extrude along path has no twist option so it's close but does not have the cable twist (

and from the closest full camera shot the effect is hardly detectable and the silhouette would probably give a bump map away at close distances. Maybe just a light and dark ramp in a diagonal pattern on the straightened UV map?

Can I model a straight tube and UV it and then transfer the map to the coil? Texturing is not my strong suit!