FireUp, et al...I am satisfied with the light output with just the two strips. I was going to use four which is why I started with the two on the ballast cover. It's over the sink in the main bath so I wanted the brightness there. After testing with the two strips, the output was brighter than the two tubes I removed. I did place double sided tape on the metal first and then added the LED strips. I think the extra holding power of the DST will keep them secure. Be sure to use alcohol to clean the surface before adhesion. (Not the drinking kind either):W.......Dennis