opposing viewpoints...always the best for seeing both sides! lol
I think the "print on silver" paper is a good idea
as long as the coloured areas will print properly for you?
many printers rely on transparent inks over a white background to produce the proper colours.
although I haven't planned this (up to this stage), I don't think it would be too difficult to include extra parts without the gradient grey.
my colour layers, are for the most part, all separate...so I should be able to remove a colour layer.
I will definately look at this once I have the repaint finished.