I had issues with puckers when I pin basted. Switched to spray basting (I like 505) and it works great. I put all three layers together, peal back the top halfway, spray the batting in strips (starting in the center) and smooth the top back on over the batting in sections to the outer edges. Walk around the table and repeat with the other half. Then I flip the whole thing over and do the same, peeling back the backing halfway and spraying the batting again. When done, I leave it laying flat overnight to dry, and start quilting the next day. Some folks iron the sandwich after spraying, but I have not found that necessary.