The color of the walls and ceiling have a tremendous impact on the "usable" light in a garage. They should be white. Of course, a white wall and ceiling will get dirty looking, but then you can repaint.
I'd also suggest some 6 or 8 foot rather than all 4 foot bulbs. Concentrate the bulbs toward the outside walls, rather than the center of the bays.
You said the project has just been started. Have you thought about a couple of skylights? Good if you intend to do work during the daytime. Also good idea to have them open in the summer if no A/C.