Thanks for your question. There are no firm rules regarding the brailling of diplomas. My personal preference when brailling diplomas is to braille the information, centering according to the layout of the diploma, and braille the information on a clear page braille lable that can be laid over the document. This preserves the original document should they want to display it, and the braille overlay allows your student to access the information contained therein. Do you have access to braille production materials? If you need further information, let me know. I'll be happy to help you out!