No one has really answered your question. I live in a small house and storage is at a premium. I have used those vacuum storage bags for a variety of items. I once put some extra bed pillows in one. They flattened down and when removed they puffed back up with a little help. I don't think your quilts would flatten permanently, especially if you rinse them and then fluff in your dryer. It sounds as though you may be storing some of the quilts for a number of years until they are needed and I don't know what effect storing the quilts in plastic for an extended period of time may have on the material.