When you start a project that will have decorative stitching as surface embellishment, make a stitch sampler. Create a basted sandwich of the same top, batting, and backing materials as the quilt. Then sew each decorative stitch in a row with the thread you plan to use.
Mark the row with the thread name and weight, needle used, stitch, stitch length and width. Measure the sample before and after stitching it to note any take-up the stitching will cause in the quilt’s overall size.