I am too chicken to change the tension on my only bobbin case and for that I haven't try it, but I have learned to do it. One recommendation I found very useful was to, if you want to sew one particular area of the quilt either quilting or straight stitch, sew it first with the top of the quilt facing up, using water soluble thread on the top (you can use regular thread on the top to save the thread). Turn it them upside down to do the bobbin thread and you will be able to see exactly where you need to be sewing. Good luck.