In my experience the humidity dome is too small to cover the cutting so I have to remove the reservoir two to three times a day to spray the cuttings until you see a root develop and that can take two to three weeks, or it has with mine. Maybe I've been taking too big of a cutting but I've had very good luck. I imagine you could tent them with a transparent dry cleaning plastic bag to keep them moist?
Another thing to consider is that you have to poke a hole well into the growing medium, assuming that you are using A/G's, and I found an ice pick or bamboo shish-ka-bob skewer to be good for that. Hank