I have made the apple core with the larger template by machine. I wouldn't whip stitch it together as I only use that method if doing English Paper Piecing. I would draw carefully around your template & then stitch the cores together with a small running stitch. Pin it carefully at each end...then in the middle & then in between . Always checking to make sure that your underneath stitches are staying on the line as well. Make each row separately & then go back & stitch the rows together. Or if you prefer do them in blocks of 4 to make a square & join the squares together.