Great tutorial!
I used a similar method to make brake ducts for the Porsche 917K I'm working on. The ducts are bigger in diameter, of course. And the wire is stretched more, leaving some fairly big gaps between the coils.
To fill in the spaces, I covered the "ducts" with Parma Liquid Mask #701. Then I painted over the mask with Tamiya Flat Black acrylic.
The liquid mask / acrylic paint combination was flexible enough to allow more bending and adjusting without opening any gaps. Looks pretty realistic, actually, and so far the paint hasn't flaked off.
Ddms