I’m trying to make a mummy sleeping bag liner, but have never seen how they close or adjust at the top. I’m assuming that its just not a long sack, but that the seam on one side opens part of the way down to give easier entry and exit.
Thing is, now much open seam do I leave, and do I need any kind of drawstring at the top?
I’ve got a Marmot Pounder 40F bag that I about froze in at 52F.

