One thing I wanted to mention is that it's probably a good idea to leave your spray basted quilt overnight to dry (or at least a few hours). I've seen a few posts about getting a sticky needle when quilting is started right away, especially if the quilter has overused the basting spray.
Also, some people press the quilt sandwich after spray basting -- although this is probably advisable only with battings that are predominantly cotton (80% or more), as polyester melts under a hot iron. Aside from probably helping the spray to dry, it compacts the batting which can make it easier to fit more of the quilt underneath the arm of the machine. As soon as the quilt is washed, the batting will fluff out again (assuming it is mostly cotton and not an iron-melted poly!).