In my experience, I do not place the labels in any specific position. But I do, always, place the tire pressure requirements right at the valve stem. There is a practical reason for this.

I own and ride lots of bikes. And most have different tire pressure requirements. With this in mind, it makes it easier for me to find the pressure requirement when seeking to remember how much pressure goes into what tire.

This is just my rational for my own personal use but it does help when one owns several bikes.