I have no idea about lights shining up or down, but, is there a way you might be able to put some sort of mirrors or tile, something above it to reflect the lights downward?
Also, I would think 5 - 100 watt bulbs would be plenty to give you enough light. If not, if there a way to bring in a light for reading, homework etc......maybe a stand up lamp that can be moved back and forth?
Just a thought. Good Luck.