Just catching up with this thread :-)
Copper is generally frowned on for fuel lines (and brake lines) as it work hardens with vibration and then cracks. I believe thats the reason it is not accepted by the IVA testers. I used Kunifer for both brake and fuel lines. Its an alloy of copper and something and doesn't suffer so much from the work hardening issue.
Great pictures! For those interested in making bodywork from ali its also worth a look at the Pembleton forum.
http://thepembleton.org.uk. These little three and four wheelers have a body made entirely of ali.
Cheers, Robin