That's a really nice cage!

What did you use to "get your temps and humidity figured out" and what are your temps and humidity?

Be aware that if you are using a bowl of water on the warm end of the enclosure to raise humidity, that warm water grows bacteria faster than cool water, so you will have to make sure it is always fresh and clean. Also make sure you are using water bowls that a small snake will not be in danger of drowning in if you are using larger than normal bowls for that size snake to increase the humidity level.

I also agree that you may need to fill the cage more so the young snake will not feel so exposed and stress out. I am not sure which size black hides you got, but they might even be too large for the size of snake you are intending to aquire. As Shelby suggested, try a pot small pot saucer turned upside down. This will function as a hide that will make the snake feel more secure as it feels its body being "hugged" by the hide.