For all those in high humidity environments and care about keeping their primers dry:
I just got off the phone with Federals customer service where i asked them if storing primers in a sealed container with a dessicant was a good idea?
here is the answer:
Mike (i believe) called their primer chemist and posed my question
their primers (esp. 210M and 205M), are not hygroscopic (water absorption from the atmosphere) but the chemist himself actually stores his primers as i have described--he knows they dont particularly need it, but he does it anyway.
so there is no real problem with primers absorbing atmospheric humidity, but it also is not possible to get them "too dry" using a dessicant in a sealed container.
So just for my piece of mind--(we all know how important that is in precision shooting) I will dessicate my primers to the best of my ability to keep them as similar as possible.