I don't worry about shelf to shelf, but I do bulk of beads on bottom and then some beads in the drawers. I have a 4 slot boveda holder on bottom with an extra boveda in the beads. In winter I stick a boveda in each drawer but in summer they come out and I only leave the bottom 5. I have fans on a timer that blow up the rear so I am circulating the air pretty often. Don't know if that will help but that's my setup.