What's the big deal with the substrate the most I've heard is when they attack something if they miss they bring in the substrate and can get an infection but if there arboreal they should never even touch the substrate just my thoughts I'm sure I'm wrong since I have no experience but hey...
So this will be my first chameleon I've got a 15-25-30 mesh enclosure with coconut fiber and moss as the substrate I know substrate is usually frowned upon with chameleons but I live in Colorado and its really hard to keep the humidity up in mesh I have a big live plant can't remember the name...