Have someone help you to remove the ballast from the fixture the tube fits into. Place it on the wall 12 inches or so above or beside the hab, and run wires down to the fixture. It's easy. That will remove it from the hab, where it will be an unwanted heat source. The tube gets slightly warm, but we can't do anything about that. I just like all the heat powered into the hab to be from dedicated heat sources like lights and CHE's.
Fluorescents should be as long as the iguana's body.
You have to shade a good portion of the habitat from the fluor. light, just so your ig can get into relatively deep shade when it wants to. When his body tells him, he will crawl under the tube and bask, then move to the hot zone to bask for the sake of the high heat which activates his gut flora.