I don't think the "rules" matter as much as the consequences. It's your house, you get to set whatever rules you like. But, you cannot make a grown adult follow the rules. So, you only get to enforce boundaries.
Think long and hard about what's important to you. But, think even longer and harder about what you will do when the "rules" get broken. Because, they probably will. That will be where the rubber meets the road. And don't threaten anything you aren't prepared to carry out.
L