Strange...I've actually not had a problem with any humidity issues in my safe...
I have a heating rod wired through the little hole in the back of the thing, and its plugged in and runs 24/7/365...As long as I pay the light bill...
And all the armaments I have stored in there are cleaned, and have a mil or two of CLP over exposed surfaces...I don't think I have had a problem with any developing corrosion or pitting on any of them, except the one I inhierited from a relative...And that "minor" pitting on the barrel has not progressed any further since it came into my care...
I wonder if a gun sock over the exposed areas on what you have in there would create another barrier against changes in humidity, which is what I think causes most problems...If the atmosphere is kept as consistent as possible, I think that reduces conditions favorable to storage corrosion...
ehhh, whata I know...
Good luck...