I don't like the idea of copper either smokey. The problem I have is that the place most of the guys look at is beside the tank - I have been doing the old paint / wait / drive routine for a few years now but even though the guy scrapped the paint from the pipe beside the tank and failed it, to be honest with you when I got under her properly and had a look at pipes above the subframe it kinda convinced me that in all honesty I couldn't say it wouldn't leak. Now, i know there is a fair difference in the wall of the steel and the wall of a 3/16 copper pipe but still, they were fairly crusty. that said it wasn't failed from being inspected there, and what it was failed on looked fine.
Now, onto the copper. Copper is banned in Germany and USA as a fix, and rightly so. It work hardens easily, and brake pipes are work intensive, both in installation and in service.
In install it work hardens being bent and flared, and in cars these actions often happen where it lands on a consumer like a calliper or cylinder. so it's worked being bent into a calliper and flared at the union, then when the pressure comes on in panic braking it sheers or bursts. In service it needs to be supported or clipped every 3 inches or so, because if it rattles or vibrates it work hardens also.
Kunifer is TUV rated in germany and is the only repair allowed - it's an alloy of copper and nickel, is easily shaped and flared like copper but doesn't work harden half as easily and doesn't need to be supported as much (clipped) either. So I'm going with that. Had to order it from UK mind - never heard of in my neck of the woods.