Ray

Flouride trays are forever. A minute sounds too short: I was told 3 minutes minimum and do before bed so it would stay on through the night. Don't worry if sometimes during the radiation it does not work out to use the trays due to nausea or whatever, just start up again when you can. I know we all sound like we have stock in Biotene, but their toothpaste, mouthwash and dry mouth spray really work.
Be sure to write out your questions you posted and bring it with you to ask your prosthodonist (amazing how easy it is to forget until you've left the chair). My dentist was and is great but had zero experience with OC so I have switched to the prosthodontist for now to deal with some post radiation complications. I know it all sounds daunting but keep the faith. You can do this
tom