First off, What have you gotten yourself into?????? Now, forget making the outfield round!! Use green to square off the area outside the baseline, thus squaring your quilt without sewing and cutting circles. I have lived at baseball games for years watching sons and grandson play ball, and I never saw the outfield as a circle. As far as home-plate, you are making a "representative" diamond, not an exact scale version, so stop over analyzing and make it easy on yourself. Good luck!! You will need it!LOL