Total thickness is 3 mm: the first mm is background (I used white), the second mm is text (I used red), and final mm is some graphics (I used black).
I experimented with thickness and liked it best when I scaled the total z dimension to 1.2mm, which gives two layers each. The final result is a bit translucent. Pictures show my Tesla Powerwall before and after. If you use Prusa slicer, it will set the filament swap layers automatically.