It is looking good, I assume that is a hide on the end with the heater. I would suggest adding a moss box, as shown in Dave's Rainbow Humidity 101 post. My 2 spend a lot of time in their moss boxes. It will also act as a second hide for the snake, and provide a good source of humidity.
Also, I am not 100% sure why, but cypress is better for brb's than aspen bedding (it looks like you have aspen bedding). I believe that cypress holds moisture better. I do use aspen with my spotted python and Cal. King, as it is so easy to spot clean.
At 45" it may not need quite so much humidity (90%). Babies need super high humidity, but adults do fine with less. I believe Dave's post talks about this. If not go to Jeff Clark's website - the link is a couple of inches above this post - it is his name. The higher the humidity the more likely mold will grow and this is not good.
It takes a while to get things dialed in, but the important thing is that you are getting good information and using it. I plan to switch my brb's from glass tanks to snake cages this weekend, so I will have to take some extra time to get things dialed in with the cages.
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Mike
1.1 BRB
1.0 Spotted Python
1.0 Cal. King