The parcel dude showed up some time in the late afternoon and soon afterwards I transferred the design to the copper sheet and etched it.
Got some pinholes in the toner transfer and covered it with some acrylic marker, turns out it's not acid resistant.. But oh well, it's getting aged and scuffed up anyway, so I don't mind the few defects.
But the thought of cutting it out with my piercing saw is not a very happy one. That will be challenging, as this sheet is almost 2 mm thick... Tomorrow, then.