One other thing you can think about, and that's !00% wool felt. My grandmother used to make the warmest quilts, and she would use a double layer, stitched together. of wool felt for the batting. This was important because her farm house didn't have central heating, and we kids slept upstairs, in the winter, where there was no heating! But we stayed warm under her quilts. I suppose you could try just one layer. The nice thing about it is you can pre-wash, and thus pre-shrink it, unlike wool batting. It comes in other combinations of fabrics as well, such as part polyester. I've been looking for 100% cotton. Not sure there is such an animal in felt! But I can't say I've looked very hard either. Just a thought.