Oops! I didn't notice the time frame of your quote when I sent 1st msg. I hope that whichever way you chose to finish the quilt turned out OK.
Maybe you need to reconsider the idea of making the back and front stitching look different. A quilt needs to be stable enough to withstand wear and tear and possible washing and needs to be stitched through all layers (front, batting, back). Since this is for your GD it will be much loved and used and will last for many happy hours of cuddling. Good luck!