Gorgeous pattern! I've always gone with the outside edge of the pinking and that has not saved me from having to square up my blocks, make adjustments, take out seams, etc. I'm with you on sewing on black, but I just did a quilt for my son with gold quilting on the black border and oh it turned out so beautiful. Back to your original question, I will stay with sewing on the outside edge of the pinking and make the necessary adjustments as I have for the past twenty or so years. Which also brings the question, why is it necessary to have a piece that is 3 and 7/8 inches? That 1/8th is going to stop the world from spinning? There is a free pattern on Craftsy for an Inverted Star and it is absolutely gorgeous, but it also required that you make your measurements exactly as directed. It takes a little longer to check and recheck, but oh my gosh it was worth every minute.