Sounds like you've got your problem fixed. One thing to remember when sewing and pressing your Dresden wedges is that all the seams you are sewing are bias so be gentle. They can stretch out of shape easily. Sometimes you can use a little starch and steam on the finished plate to shrink the excess out and make the circle lie flat. Starching all your fabric before cutting your wedges helps too. And there's no shame in having to take a couple of your seams a little deeper once they are pieced to make the circle lie flat.
One of my quilting friends calls me the Queen of Dresdens because I love making them in so many different variations. In fact, I just finished a quilt top using Geta Grama's method for turning them into square blocks. Easier than appliqueing all those circles.