The problem with too low a humidity is the moisture gets drawn out of wood stocks. It is a balancing game between humidity and damaged stocks. Of course, this assumes you have wooden grips or stocks on any of your guns.
oh yeah theres a lotta wood in the toy boxes but I figure with the number of times I open them and the amount of moisture I see in the desiccant tubs that its plenty wet hence the worry and amount of drying I do. your right though its a balancing act. my thing is I am scared that one day I wont go in them for a longer length of time and when I open them up there will be mold and rust covering everything. I have seen this with several other guys safes and it scares me to death so I guess risking a cracked stock from over drying to me is better than a lotta rust and mold.