Panels are tough to use for me and I debate over and over what to do with them. My advice is to move slow and develop a plan as you go. I first decide if it needs a border, put it on, then what kind of block does it need, make them, and so forth. To me, it seems the best panel quilts have blocks that "float" around them. As long as you don't try to sew block to block in a set size, the quilt dimensions are not set on the dimensions of the panel