
Totally the client's choice. Include both options on the approval/sign-off so the client has a good visual. Make sure their choice is clearly marked, so you don't get that dreaded head tip and hmmmm when they the completed job.
That's a terrible feeling (getting the head tip & hmmm) even if you tried to convince the client they were making the wrong choice.
Other than race cars, I always slant to the right on anything else.
The only thing I see drastically wrong is on the left side of the Police car the "Dallas County" is way to far forward. It's centered under Sheriff on the right side of the car and looks good.