I have a 300 count or so humidor, probably a little over half full. Right now I use three on each level for a total of nine, the humidity in the room is about 17% right now, and this maintains 65% in the box. When the weather breaks, the humidity in the room will rise, and I'll drop it to two per level. No racks, just lay the packs on top of the sticks. No problems for me by doing that. I believe Boveda says the same thing...no harm to the cigars.