Photosensetive = They really do not like light.
Bite Reports (just look for the P. metallica if there are any):
http://www.arachnoboards.com/ab/foru...6-Bite-Reports
Also Bite Reports on You Tube (Here is one for RobC when he got bit by a 10" P. ornata):
You can possibly get bit durring cage feedings, cleanings, any time you open the lid, cage transfers, breeding etc.
The humidity is naturally high where I am. I rarely ever mist my P. metallicas but they always have a nice size full water dish at all times.
I have heard of the humidity issue yes. Mainly with avics and species that require really high humidity.
If you search aracnoboards and surf youtube videos you can find a wealth of information (you have the weed through the crappy info though).