I have done quite a few PCB-s myself with various techniques such as tape, pens, decals and the odd one with photo-resist and a laser printer. I just figured that printing directly on a brass sheet and (as you pointed out) paint the whole backside would have been the easiest way. IF the ink can take it. But right now I don’t have the stuff needed to test this.

I have run thicker paper through the printer so that part might work if the printer doesn’t bend the sheets too much.

Leif...