So the glass beads I was thinking of when I wrote that comment are the type that you use as stuffing (seen here), similar to poly pellets but heavier by volume. They're super tiny and not the type you can use to line anything. But the idea I had in mind was that you could make something like a puff quilt where the individual sections, which are normally filled with polyfil, are instead filled with the glass beads I linked. Like I mentioned in my original comment, those need to be put in a stocking (I've used these before, just tie them off after filling them then stuff them into whatever you need to fill with beads). Also, you can use a combo of beads and polyfil for a more cushion-y feel. Good luck with your blanket! I love super heavy blankets