I don't think its a matter of taste, the car was designed to have a large rear plate, hence the plinth/appature, the same as the P5. it's totally fine if people prefer a smaller plate, and that would be a matter of taste, but I feel the "Correct" plate would be a large one.

Back to the topic, Welcome to the Forum, this is the place to be if you own a 260. (I will leave plate choice up to you)