Another thing I learned when visiting China - never vacuum pack or purchase vacuum packed white tea. There is something about the vacuum process, even with a nitrogen back-fill, that causes the tea to lose that soft, pillowy feel. If vacuum packed, it will come out looking like the lowest grade fannings, crumbly and hard, in a very short time. Must be the vacuum process destroys the moist feel or something?
When in Guangzhou and Nanning for my last visit, friends suggested always using the ziplock type triple-layer mylar/foil bags. They put the tea in the bag and squeeze out as much air as possible (not TOO much squeezing, please!), then seal the bag. If the bag still shows the outline of the tea inside the next day, they say the seal is good. If not, they discard and use a different bag.
I have several different cannisters for storage, but for white, my friends tell me that even the air remaining in the cannister after filling with tea will cause unwanted oxidation. I put the sealed bag in the sealed container.
Keep in mind, good white tea is a "single-harvest" tea and storage is more important than with any other kind of tea. There is simply no way to have "fresh" white tea after August or September; it's all going to be "old" by then. I usually still have white tea from the previous harvest when the new harvest occurs. I don't like to run out and have to wait for the new crop, so I always ration myself, particularly toward December. Come March, I'm ready to finish up in anticipation of the new tea. It is not quite as good in February and March as it was for the preceding months, but it still retains that unique feel and flavor. It is certainly better than not having any at all.