I so depends on the quilt I am making as to what bat I use. The other factor is how close I am quilting things together. With closer stitching I like a low bat and when using I high bat I will quilt further apart so that is puffs some with washing. I am a big fan of cotton bat for children's and baby quilts for safety reasons. Then on some quilts I use what ever I have here that will fit the quilt.