Hi Kristen,
I would recommend hand misting for your brevi's. I think having a misting system, even on a timer, will be too much and keep everything too wet. b/t the soil, plants, and occasional misting or dripping is fine to keep humidity up and frankly they don't drink very often. As I am setting up the new tank (yup, still working on it!) I am going to devise a bowl on stones for a dripper (plastic cup with pin hole in bottom) to drip onto leaves and then as much as possible be caught in the bowl which I will dump and clean daily (at least). If your substrate gets saturated it will difficult to dry it out and keep humidity up. The way I regulate the humidity is that I have a piece of cut plex-glass that fits right into the top of the tank and cover about 2/3 of it and then put the screen on top. Then I take it off sometimes to let things "dry out" and this is working great. I always mist before bed and put the plexi on for the night. Rather long-winded (what else is bew? LOL), but thought I'd tell you what I have found to work.
BTW, they hate the misting, so best to aim on glass or a plant 
lele
>>I would love something not quite so dumb looking to go in my vivarium so I didn't have to mess with all the ugly hoses and such running every direcction...but I guess those are necessary if you're gonna have a misting system.
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>>Ugh...
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>>Kristen