I flattened one side of each reflector so I could overlap them, since you have to keep room in the hood to fit the top of the filter system. So the ballasts are pretty much butted up against each other. Then we secured each ballast with two bolts, using the mounting holes on the ballast. We did have to drill through the reflectors, but i think only one side each as the other side cleared the reflector. But what we did though, instead of having the screws go through the hood, making it unsightly, we used 2-part marine epoxy to basically weld the head of the screws to the inside of the hood, effectively making POSTS that the ballasts then slid on to, with a nut to secure them. So from the outside, nothing is visible.
The only downside to all this is that the hood is now pretty heavy and you have to be careful taking it on and off.
The fans are not strong at all, but they have been enough for this tank. I only have one of those cheap stick-on temp guages, but it seems to sit right at about 80 degrees.
And everything inside the tank is just loving it! Sooooo much better than those stock P.O.S lights!