I 3rd Maniac quilter's suggestion. Cross hatch in white thread and go right over the embroidery but do it on point (so the cross hatch forms a diamond grid) and a 1" grid. I saw a picture of one done this way recently (red work hand embroidery) and it was fabulous and actually took a ribbon at the show. The quilting over the embroidery did not take away from the hand embroidery at all and it gave the redwork a classic, timeless look. For your red sashing I would do feathers or a simple egg and dart design. I would do pumpkin seed flowers in the white cornerstones.