Whenever I use RR's I use a dome to cover the clones, removing 4-5 times a day to let fresh air in and to spray the inside of the dome with ph'd water. If using an EZCLONE I do not use a dome, I just mist very lightly with ph'd water once a day until they root.
I also keep an eye on the temperature of the water in the Cloner and try to maintain 75 degrees throughout the cycle.
It seems that temperature control is one of the main keys to keeping the clones happy, mid 70's if you can. Another key is fresh air it helps them harden off a little at a time.