I use old towels or terry cloth bathrobes in my potholders , Using two thicknesses with the backing and top is plenty thick for keeping the heat from burning. The recycling part is a big plus. Ihave also used old sweatshirts, recycled matress pads, old felted/moth holed wool sweaters. At times I have used many thinkness of flannel ( prewashed/shrinkage). All will quilt just fine if you are machine quilting and using a walking foot.
I agree that one layer of batting is not sufficent.