a really good digital humidity monitoring device is this one. it's called an accu-rite...



this one displays time on top, temp in middle & humidity on bottom as a percent. i personally use my temp gun to monitor surface temps in my girl's terrarium so i had no use for the corded probe that measures the temp so i snipped that off. i use the accu-rite to monitor humidity and i have the time set on it so i can record the time when i check and record the humidity.

some awesome identical hide boxes like these...



very similar ones can be found at reptilebasics.com. it's where i got mine. get the size that allow your snake to curl up inside nice and tight.

as stated already, that light is only gonna suck out the humdity. bp's are nocturnal so a light that is on 24/7 will only stress them out.

an awesome substrate is exo-terra forest bark. i got mine at reptilesupply.com. my only complaints about it is that
1) it's dark color hides poo very well and thats no good for someone like me who will reach in blindly to "re-adjust" the bark that's been displaced by a snake constantly re-decorating her home, lol. ew.
2) if the bark is handled too roughly you can get tiny splinters but those are easily avoided by handling the bark gently.