I did mine in Cupro aswell, and whilst it's harder than standard copper to run - you won't need to do it again for the life of the vehicle (with any luck!)
I had to get one of these:
There are a load of different sellers on eBay who do them, but it is designed to be able to do Cupro and steel lines, with single and double flares... and the best bit... it can be used on the vehicle, so you don't have to try and get the line the right length, flare it, put the unions on and then weave it into place... I just ran my replacement lines off the reel, with a bending spring on it to do the curves/corners, then cut the pipe to length and flared it.
Oh, and whilst the pipe is 3/16" (or 4.75mm?) the unions are M10 threaded rater than imperial. I found that the SAE flares done on the flaring tool worked fine.. I wasn't sure whether they were SAE or DIN flares, but as the SAE looked most common, and it did the single/double flares for both sides of the unions, I went for that.
Been on 4 years with no leaks, and joined up OK to the existing lines behind the front wheel arch liner!