Just to give you a little info on my situation for whatever value that would be to you. I've got four 120 qt coolers set up like this....
two coolers full of boxes & cabs tetrised as tight and full as I can get them
one cooler half full of boxes and about half of the remaining space with singles in baggies
one with four cedar trays of singles and then the rest of the space full of singles in baggies
All of them are running beads keeping the RH at 65%. We keep the inside of the house at about 74-75 deg which is plenty cool and comfortable here. To be honest I've never paid much attention to the temp on my hygros but after reading this thread I just checked out of curiosity. I've got one of
these in my desktop and one of
these in each cooler. All of them have been checked (RH wise) with a Boveda calibration pack. All of them are showing either 76 or 77 deg. Who knows if they are spot on accurate as far as temp goes. Not sure how the inside of the cooler could be warmer than the temp outside of them! They have been set up like this for the last 4-5 years and I have never had a problem with mold or beetles.
As far as the beads go, you don't need near as much distilled water as you would think to properly hydrate them. For 1/2 pound of beads you don't need but about 10-15 ml (about a tablespoons) and for 1 pound of beads you only need 25-30 ml (about two tablespoons) of water. I have all of my beads in nylon hose and have never had an instance where I added water and then had water leak out of the beads. I always re-hydrate them and put them right back in the cooler. How often you would need to re-hydrate them will largely be depended on how full your cooler is. When you get that many cigars and that much cedar (boxes) at a set RH, the environment really stays pretty stable. I only add water to my beads probably every 1 1/2 to 2 months