I don't know how you begin to baste without having some pins in it! And I agree that if you are going to pin heavily enough to keep it stable to baste, well just go ahead and completely pin baste. I suppose you could spray baste the top to the batting and the batting to the backing but I would still be concerned about shifting. If you did attempt it that way, I would start my basting in the center and work my way out to eliminate any puckers.