i preffer highres scans with dimentions in millimeters.
but straight highres pics and inches can also be used
i know that 1 inch is 2,54 mm.
i have some space left in the second sheet, and can squeeze in some decals if you want.
i do need to create the file though, so it will delay the rest of the print, but as i do this on the side, its done when its done
i print when i am ready, thats the nice thing about the way i work, luckily its not my main job