I have tried a number of methods and now use a combination of techniques. I usually use freezer paper ,but do not starch or iron the seam allowances under. Just pinch press around the shape with my fingers. I needle turn the fabric with the freezer paper in place, then remove the paper with tweezers in the last one to one half inch of stitching. I get a nice turn on the fabric, without having to mess with the iron much.