Do I mount my T8's vertical or horizontal?

[strnge]

Wich way should I mount my T'8s? The support beams are in the way, so the lighting will be cut off at points, so this is why I am looking for advice. As you can see it's dark in there. I am moving in on next Thursday.
Here is the garage with the painters car inside:

 

[custom1]

How many are you going to use?

If you have enough headroom I would put some right on the bottom of the beams and then sprinkle some around on the floor/ceiling joists. I wouldn't worry about which way they were running.

John