I use a pellon low loft fleece, I think the number is 987. If you can't find it, you could try a thin batting and basting spray or hand baste. You'd get a similar effect. Although if you do it that way, maybe cut the batting/fabric a little larger and trim after quilting.
I did one mine with fleece/quilting on the outside, but interfacing on the inside. It's got a little more body, but was very thick to sew. I also did a few as the pattern said with batting on both the outside and the lining. They came out fine too.
Holler if you need help! There are many of us that would be happy to assist you. :)