I guess I can just ballpark it. The front of the slate is about 70 inches wide, which would make that grill about 28 inches by 8 inches. That converts to about 700 mm. So outside pieces would be 200mm(maybe a little more) and inside piece would be 300mm.
Thanks for the feedback, but I'd rather DIY the whole thing then pay a couple hundred dollars to a print service. Worse case I would buy my own super expensive printer. I'm just trying to get an idea of which way would work best based on how big it is.
Slatelets and headlight covers look pretty easy to design and print. Any info on the dimensions of the area between the headlights? I'm guessing we'll have to break it up into three pieces with seams or something to get it to fit on a normal size printer.