The little "bumps" in your circle could be from the stitching, or maybe just not evened out from inside. I think I would use a very small running stitch, and might even mark the 1 /4 inch seam allowence all the way around before stitching. When it is stitched and turned, use a tool of some sort (dull table knive would work) to run around the inside, pressing lightly as you go. I think this would strighten out the "bumps" . Also, I'd be willing to bet a little "bumpyness" will never show in the finished block. Especially if using a print fabric. I think most hand piecing is done with a small running stitch, taking a back stitch at the beginning and ends of the stitching. At least that is the way I have done it. Best of luck to you. I am watching this thread!!