Copper is bad (tm) for fuel or brake lines. Basicly its not rated to do that job, and you will get defected if its seen by someone who might do that sort of thing. As for the residue, it's not somthing i've hard of first hand. *shrug*
The alloy pipe BansheeBuzz mentioned would be the go, but a steel line would be the best option, especialy if its under that car where the standard pipes run. Also, you can get proper outer braided fuel line, but its like $11 per meter. Don't skimp on this as getting it wrong could result in a burnt out car!
As for the flaring kit, most automotive shops should have a gadget to do this. It should be able to do all the usual sizes of pipe used for fuel, clutch and brake lines.