For leaf already stored in bags, I just move them to the kiln as is, and leave the bags open. For leaf hanging in my shed, I simply wait for two or three consecutive days of higher humidity (like several days of rain) to bring them into case naturally. (The weather wunderground.com 10-day forecast graph can display an RH curve, so I can pick an advantageous day and time of day.) With strung leaf that is crumbly dry indoors, but needs to go into the kiln, I usually mist it ahead of time, before moving it.
You can certainly mist them for handling, if you need to. If your kiln is providing its own moisture (e.g. Crockpot with water), then the humidity will be fully dependent on that.
Bob