With a Prince Charlie, and I mean to wear it properly, to me anyway it is worn with the waistcoat, therefore no belt as a belt will cause the bottom of the waistcoat to jut out. This is the way I wear mine with the waistcoat, always with the waistcoat, as this is the way it has been traditionally worn. With this type of clothing there are certain rules that must be followed to be proper, you would not for example wear sneakers or hiking boots with it so I would say follow the rules of good decorum when wearing the Prince Charlie.