How do I specify License Plate numbers' place?

I have a license plate mod that I'm working on. I don't want the text to go above the black box. how can I do that?

 

Not sure if I understood you right, but changing the text size value might help...

 

This is an example if you didn't understand me. See how the text don't go above the oryx? I tried the mod just right now and wrote a DDDDDD plate number With no spaces or anything.

 

Well what a coincidence...