I bought a Western Mountaineering Ultralite, it's extremely puffy. It came with a stuff sack, and when I pack it down it is extremely tight. I'm overly cautious with new gear, and this is my first nice down bag. Is it safe to use the stuff sack it came with, or will it over compress/damage the down? How long is too long to compress a bag? I plan to hike till dark on parts of my thru hike, so is over 14 hours of compression ok?