Yes, you can double the batting or you can do 2 different battings. A lot of the ladies in my long arm guild use one layer of cotton or 80/20 cotton/poly with a layer of wool on the top. It could be all natural and it really makes the quilting pop! I think the quilting from a long arm stands out more because the quilt is stretched somewhat onto the frame and then the machine really punches the fabric more than a home machine. ( this doesn't sound good, but I can't find the right words to explain it) I think a quilting machine is a more industrial machine and makes a more pronounced stitch, perhaps. I have seen some awesome quilts done with 100" poly......(Ie...Dream something) , but I personally don't use poly either. It can melt onto skin in a fire and it just doesn't breath like cotton or wool.