I would try to "true" them with starch. Sharon Schamber has some good videos on how to do this. Here is a link to one on how to true a block (would apply to a panel too; just need more space to pin):
http://www.youtube.com/watch?v=v-3RIWhBvcA
The trueing keeps everything lined up while you are piecing and quilting. Something that starts out wonky benefits from more quilting rather than less, because the quilting will help keep the fabric from going wonky again.