You probably already do this, but had to mention it just in case. Do you have support set up for the parts of the quilt that are not under the needle? That is so the weight of the quilt is not pulling at it and making it pucker? I just set up to start FMQ on a pretty big quilt and set up a table to be behind the sewing machine and a TV table to the side so the quilt will be supported while I quilt.