Good questions. Light cycle is natural. I leave the blinds open as the spare room/office is in the northeast corner of our house and protected by trees. Very little traffic in the room day or night.
I do not have a timer on the UTH. I will add one when I add the UV lamp. I did think the tub might have trapped in too much ambient heat as he did prefer the cool side but would use the warm side hide as well.
The tub was opaque until I covered the sides this week.
The glass enclosure now has the same set up but should be cooler. The glass front is, of course, much clearer in the front which is nice to see him with more clarity now but it's anybody's guess how he responds.
Nice to get an update on your diamond/jungle. Happy he is using his perch during the night.