Upload & Sell: Off
In a 10x14 room, it won't matter much between a 5 foot umbrella and a 6 foot umbrella. They are both going to spray light every where. For 2-4 people in a room that small, a 42 inch would be much more manageable.
You also need to think of you ceiling height. Do you have enough height to be able to have the umbrella pointed down at all?