I would get a large hand full of sfagnum moss, get it soaking wet, ring out most of the excess water and then place it on the warm side of her cage or tub. The heat will cause the moss to evaporate thus increasing the humidity inside her enclosure. I would not mist the eggs, only increase the ambient humidity.
Another thought would be to go ahead and place the eggs in a plastic shoe box like the one I showed in my post. Drill a 1/8 inch diameter hole at each end of the box about an inch from the top. Mix equal parts of vermiculite to water by weight (the key is to mix it by weight) and place the eggs on the cool side of the mothers enclosure. My guess is the cool side is somehwere around 82 to 85 degrees.
Initial temps are probably not that criticle. I would be more concerned about getting the eggs too hot than too cold.
When I used to breed colubrids I use to incubate the eggs succesfully on the top shelf of my closet, with out any heat.
Good luck and if you'ed like you can call me at (408)981-6694
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Brian Gundy

www.for-goodness-snakes.com