JRB compression sacks pack a three season quilt to to 7x7x8...Down is very resilient... no issue over a few days compression,,, Have used these sacks for hundreds of nights with no ill effects...FWIW that is about 1/4 of a side harley case.
Ounces to Grams.
... Largest supplier of camping quilts and under quilts...Home of the Original Nest
Under Quilt, and Bear Mountain Bridge Hammock.
800 595 0413