If you do vacuum seal, you may want to leave a little air in the bag to allow the tobacco to age. Per this from GLP:

"Vacuum sealing is great for vegetables and coffee, but is pointless for tobacco. Tobacco needs some air to be locked in with it , at least to begin with, in order for it to age. A perfectly vacuum sealed container will likely keep the tobacco "fresh," but it may not really age the way we expect it to. I'm more than a little suspicious about the heavy plastic "bags" used by most of these machines. They hold moisture in just fine, but they really don't prevent gas exchange, and I'm not sure they're truly able to stand the test of time. Tins are best. Jars are a close second. The special high barrier bags we used for a while for our 8oz packaging have several layers, each designed to be impenetrable to a different sort of molecule. I've conducted extended tests with this material, and am satisified that the tobacco will age nearly, if not as well as in the tins, at least for the short term. They are only slightly evacuted to facilitate packing and sealing. For best long-term aging, though, I still recommend tins." - GLP