Decorator Rule of Thumb for size of light fixture and ceiling medallion:

How to decide what size hanging light fixture and medallion for your room: Take the width W and Length L of the room and add these two numbers. Use these numbers, but in inches, and this is the diameter for your fixture. (For example, if your dining room is 10'x14'; 10+14=24. Medallion should be 24" or larger.) Select a medallion slightly smaller OR larger (preferably larger)than the diameter of the light fixture. Where to hang? Hang 30" above table in a dining room or kitchen -- add 1-3 inches higher for each foot of ceiling above 9 ft. For Ceiling Fans: Be sure to select a medallion with less than 2 inches of projection from the ceiling.