One of the best places to look for very in dept info on iguanas is
www.anapsid.org Melissa Kaplan has done a lot with iguanas and I have spent a lot of time on her website, she has a lot on their diet down to why certain food are not good. Spinach for example is okay for a side dish but it Can cause a loss of calcium in iguanas.
I know some a bout igs, I am constantly being given Igs because of my rescue, I have some answers but not all. I am always learning more because science is always changing.
Diet-Green such as Collard greens and Mustard Greens are best for the base food, I use a 5 different ingredients rule with my Igs. For example I use Collard Greens, Kale, Mustard Green, Leeks, Spinach, Cilantro, and Parsley. The latter four are used mixed in with the first 3 mentioned. This basic diet is great for Igs, I personally stay away from carrots and especially from Lettuce which has no nutritional value and has very little calcium. The food list I gave is high in calcium which is VERY essential for iguanas. Without calcium their bones will not grow properly and will be brittle and break easily. Always have fresh water available in a tub big enough they can sit in.
Humidity-Think of Florida. Iguanas are almost native there now, they thrive in Florida weather. High humidity helps with their shedding, there respiratory system and overall health. Iguanas swim very well they stay by the waterside so they can easily slip away or just get wet.
Temps-Think of Florida again, they love the warmth. With humidity temps need to be on the high side of their cage. I keep my Igs High side at 90-95 degrees and low side at 85 degrees.
Cage-They need a lot of room to run, as they are very good at doing while young. They are not like snakes and can do okay in small spaces, these are animals that can roam a full acre and still want more room. A lot of people let their Igs free roam-meaning they are allowed to go just about anywhere around the house.
Books-One of the best books for complete info on iguanas is The Complete Iguana-The Ultimate Owners Manual by James W. Hatfield III he has spent a lot of work and has great knowledge. His website is
www.Iguana.com
I hope this is helpful. Feel free to PM me if you have other questions, if you are lucky my little brain may have an answer for you.