My advice would be to use stabilizer on the backs of the shirts. I know you can make them without it, and the quilts will be just as nice, but stabilizer makes it SOOO much easier to work with the shirts, both when piecing and when quilting. I've done both ways (with and without stabilizer) on the longarm, and with stabilizer is easier to work with on the LA. Just some personal observations in case you are sending this out to a longarmer.
Christine