The problem I see with this (I know I'm being a spoiled sport - SORRY), is unless you use a heavy duty zipper. Your zipper will pull apart. The plastic zippers by the yard are small plastic zippers. Not made to be pulled in different directions at the same time (over large spaces). The longer the plastic zipper is, I have found them to be weaker (less stable). So if you're sewing down the middle using two twin quilts, if person A turn away from person B (now A & B are back to back). But in turning both A & B roll away from the middle of the bed pulling quilt with each of them, you will have a zipper being pulled apart (maybe not the first time, but it will happen). You have to use the small plastic zippers, because this lady doesn't want the zipper showing. So I see a zipper pull apart. Again SORRY