Q: A sacramental question. Could a celebrant begin using mustum at his Masses for himself, or would he need explicit permission from the bishop? From the document I am reading, parishioners can simply make the request to a priest for this or low-gluten hosts, but I cannot tell if different for the celebrant.
A: Here are the norms from 2003, still in force: https://www.vatican.va/roman_curia/congregations/cfaith/documents/rc_con_cfaith_doc_20030724_pane-senza-glutine_en.html .
You may recognize the name of the cardinal who signed them.