Queenbarbiej - you finish the rounded edges before you sew the petals together. I simply traced the curve onto the wrong side of the petal, then I cut muslin squares for the facing and sewed along the traced line. Then I used my pinking shears to trim off the excess fabric, turned and pressed. I sewed the curves with a rather short stitch to give a smoother curve.
I recently bought the large set of the Perfect Circles templates, they go from 2.5" to 4". I used a pencil to mark the exact center so I could get them lined up correctly for tracing. I also them to create the centers. They are heat resistant
At that point sewing the petals together is the same as when you sew and turn the points first..
I had always looked at these and thought that turning the outer edge after all the petals were sewn together would be a nightmare, had no idea you did it first! I've been very surprised to find how easy and fun these are to make.