Bottom right for me,
1 simply layout for the public to remember,
2 simply layout for the prospective customer following to read on the car in front,
3 simply layout so the printer won't mess up.
I would print a couple of different colours off on paper and test them on the rear screen of a couple of cars, tinted glass can affect the ability to show through the glass, I know this cause I work in a main dealer and ours are pretty cack through privacy glass. HTH