They'll work, but I doubt they'll last 6 months... maybe 3 from the first day it is opened depending on how much you open and close the bag.

Like Kevin7 said, go get yourself a humidor and a good humidification device and set it up properly. No matter what you buy you're going to want to stabilize the cigar for at least 3-4 weeks in a proper environment before you smoke it.

There's a bunch of good threads here on seasoning a new humidor. Make sure you do it right.