For Pt/Pd printing (I have not tried Kallitype), I have one small humidifier and one 'room' size humidifier. I fill the sink with warm water, turn both humidifiers on, turn a small fan on and go have coffee. The darkroom, 6x12 foot, goes from 28% to 50% in about an hour. When I was printing ziatypes (which need a lot of humidity), I would turn on the shower in the bathroom for about 20 minutes so the room was good and steamy, hang the paper and let it be for around 20-30 minutes. Do you have a large room? 10 hours is a long time!