I also have a Wiggys sleeping system - they say that their bags can be stored in their compression sacks. They actually sell some of them vacuum packed for emergency and military kits, and guarantee they’ll regain their loft when opened.
I think they say it’s ok to wash them in an agitator machine, too - but check on that before you do. They’re very durable, and they claim to retain something like 85% insulation capability when wet, IIRC.
At 2.5lbs for 35F, it’s a little heavy, but still great for durability, compressability without worrying about loft, and not too bulky when packed, though I’m sure there are smaller ones out there.
Anyway, for storing other bags, pillowcases work well. They’re big enough that the bag doesn’t compress and still let the bag breathe better than a stuff sack. I guess the best is hanging by the foot of the bag, but that’s not a practical solution for everyone.
Jeff
Jeff