Overprint packaging question?

I'm trying to set up up an Illustrator file for a packaging artwork. The job is litho CMYK + 2 Pantone spot colours. The Pantones are 419 C and 8641 C (8461 C is metallic). The sequence of printing is (according to the printers repro guide) is K, C, M, Y, Spot, Metallic. My artwork (partial image shown below) is a CMYK image with 419 C as the background colour (basically almost black) with a metallic gold pattern (8641 C). As you can see from the image I've got overprint (0.1mm) set on the 8641 C). My question is what do I do about the shadow from the Karahi dish which is on top of the 419 C and Metallic Gold (8641 C)? I don't think I can use black as that is the first colour printed (So I'd someone have to reverse out). I want to use the 419 C to overprint the Gold, but the gold goes down last. I assume the gold will be quite opaque, so I'm not sure how the shadow (419 C) will come through with the gold on top? I suppose I could leave tiny holes in the gold for the black to come through but how would I set that up. I'm stumped. I suppose I'm hoping the printer could swop the 2 spots so the gold would go down first with the 419 C on top. But I bet this is because the metallic ink doesnt like having an ink on top of it? Any thoughts greatly appreciated.