I double bat many of my quilts. A layer of cotton with a thin layer of poly. It does make for a warmer quilt, as well as give the quilting more definition. I have my bed size quilts professionally quilted , as the two layers of batting make it a difficult to quilt on my machine.

I have been double batting some of mine more for the quilting definition than warmth, it hasn't presented any problem and seems to drape just fine. I have been using an 80/20 and Hobbs Poly Down and have to say I really like it.