This first picture here shows how I held things in place while I tack-welded the nut on the plate. The screw drivers held a gap between the edge of the disk and the caliper. We don't want any dragging there, either!
The second picture shows the bracket mounted with the nuts welded on. I have a crappy flux core welder, but it is more than up to the task for this sort of thing.
After welding, I used the wire brush disk on my bench grinder and brushed the heck out of it, then zinc plated it with the Eastwood kit.
I saved the short brake line from the Milano that I scavenged these calipers from, and I hoped to reuse it. It did have the right end fittings, but was the wrong shape. I read the stern warning on the Centerline installation instructions for their disk conversion kit, "Thou shalt not ever, ever let the brake line touch anything or vibrate against anything!" With the fear of God in me, I very carefully fussed the brake line into a usable shape, no kinks.
Take a look...