How would you light up a sps dominant system?

[MitchM]

The fixtures themselves are 46" and with a bit of an overhang the space was about 5 1/2".
Both fixtures were pointing the same direction, the exhaust outlet of one was blowing into the side of the other, but with the intake fans on the top and sagging acrylic lens they come with, there was lots of room for fresh air to enter and hot air to excape.
Since I've replaced the initial ballasts, I haven't had any problems which makes me think that the original ballasts were the problem. (in addition to the plastic LED reflectors)