We are seldom asked to give advice on full-sized habitats like the one you describe. Kudos and congrats to you!
I know you've read about green iguanas, and this is also a great place to find detailed information about the care of captive green iguanas:
Do check out the "Ch-Ch-Change!" article. It can give you information about his personality when his fear of change goes away.
Mount the UVB tubes directly over the top shelf, and place the top shelf about 24 inches from the ceiling. This way the fixtures mounted on the ceiling (such as the general lighting) can shine down onto the long top shelf. Give him a shady spot on the cool end of the top shelf.
I think if you light and heat the upper zone of this habitat, it will imitate iguanas' natural jungle habitat, where it's always shady and cooler on the ground, and has strong light and more heat high up in the canopies. In your indoor habitat, the general lighting that comes down from the top lighting fixtures will illuminate the ground level enough.
IMO you should place his food and water on the floor, so that he gets at least some exercise from climbing up and down. You might have to provide some heat to the area where the food is.
I recommend that you place the UVB tubes in such a way as to have 12 inches minimum from the bottom or the tubes' glass to the top of your iguana's back. 10 inches or 8 inches might be better, but you will need a UVB meter (SolarMeter 6.2) to measure the irradiance at different distances. The tubes should be mounted at one end of the habitat, instead of centrally, and the center of the hot zone (95-100F) should center with the UVB tubes. This creates a hot side - cool side along the top shelf of the habitat, so your iguana can choose the exact temperature in which to bask. He can also retreat to a cool place, at 80-85F. This is all on his upper shelf.
Keep in mind that UVB dissipates quickly with distance. I read somewhere, so I can't give a citation, that the UVB irradiance varies as the inverse square of the distance to the object being irradiated. IMO, and I'm open to correction on this, there is no harmfully close distance to the 10.0 tubes. I have long-term experience with that fact.
Use a lamp timer to plug the UVB tubes into. That way they will turn on automatically at 7:30 AM and turn off at 8;30 PM. When the UVB lights turn off, another timer will take control of the CHE's. Try hard to use thermostats to automatically and accurately control the heat. BTW don't connect a thermostat or a dimmer to normal fluorescent fixtures. 80f on his shelf at night, and during the day, 95 to 100F at the hot spot. Spyder Robotics has the best, and Zoomed has several models.
For general lighting in a cage that big, I would use 2 ea. 4 ft. long 10,000 CRI fluorescent tubes (you can find them on aquarium supply websites). Avoid the blue-tinted ones. These white-light tubes contain most of the visible spectrum. I would mount them to the center of the ceiling, at the end of the cage where you mount the UVB tubes. Provide your ig with a shady place to retreat to.
Do your infra-red bulbs project an orange colored light? If so I would try to sell them back and then use CHE's for all heat. The dark blue and dark red "night lights", including the infra-red lamps that I've tried, disturb iguanas' sleep. Perfectly dark at night is safest for iguanas.
You have to decide if you want to heat and humidify the entire inner space of the habitat.