Agree'd, you're not going to get much light out of those. Plus I wouldnt trust the double stick tape holding the whole assembly on the roof.
If you haven't noticed I sell some sweet LED light bars that you can get in single row and double row. You can see all of my products at www.ledbarsusa.com and I have a group buy going on for the 30" SR bars right now in the classifieds if you'd be interested in that size. So far everyone that has bought one has been happy. They are also very well priced for the light output you get from them.