I love them. I don't think they are great in a wooden humidor unless you have a good seal, and have a couple more than the manufacturer suggests. They are very accurate, and result in no humidity swings.
If you use them with beads, the beads will pull the moisture out of them.
How many would you suggest having in a 100 count humidor with about 50 or so sticks? I currently have the manufacturers recommended 2 packs in there right now, but the humidity is at about 74% would it be a good idea to throw a couple more in?
Are you using the 72% RH packs? Your humidor has to be properly seasoned. If you know that is good, then I would add
at least one more than the site recommends. Go by the size of the humidor, not the amount of sticks. The more cigars you have in the humidor, the better. I use mine in the cigar boxes. Right on the cello, or above the cedar sheet on naked smokes. The 74% humidity raises questions on either your Hygrometer needs to be calibrated, or you have some pretty moist sticks in there.