I don't exactly know what you mean by quilt laying flat. I want smoothness on top and front. When I use basting spray I smooth the quilt back on top of the batting, then turn it over and smooth the quilt top on the batting. I have one of the longer Slide Lock rulers and it's great to smooth the quilt. Works so much better then my hand. A Gripper on a long wide ruler would work too. If I find a wrinkle I pull the layer off up to the wrinkle and restick it.