With humidity that low i'd leave them covered a bit longer,misting just enough to keep the clones from wilting forces the cutting to root much faster,just keep an eye on the cuttings after you uncover them,no matter what they will not die right off,if your not misting them enough they will wilt & can be brought back to full health with a misting.
Temp is very important,keep the cuttings warm,around 80 degrees is perfect.
Length of time till roots are visable all depernds on conditions & technique,when i was strictly using the humidome it took on average of 2 weeks to see roots,sometimes a bit longer,the method i use now in most cases i can see atleast the tap root poking out within 1 week,some clones have an assload of roots sticking out of the plug in a week.
The main thing your 1st time cloning is to keep them alive & healthy looking,if you keep them from wilting you will get them to root,be patient with this clone,then on your next clone you'll have confidence & knowledge,at that time start learning a technique.
Cloning is very easy,just chill,keep them warm,mist them occasionaly & your in there
