The amount of light from a light is reduced by the square of the distance. With your ceiling height, this becomes a problem. Use a T8 Tube fluorescent light similar to what Griot's has (
www.griotsgarage.com). Also the amount of light you need is dependent on your age also. What you could see when you were 20 (50W) will require 150W at the age of 60. I didn't buy the Griot's lights but found similar lights from a commercial lighting distributor. I have a 13' ceiling height in one bay and 10' ceiling height in the other two. I added more lights to the 13' to counter the issue of distance. I do not have any problems with enough light at the age of 62 with these types of lights.