I FMQ'ed a king size quilt for son and dil that had the entire "Our Father" written in, what else, quilting. I started on the bottom center and went in a complete circle around a center border. It was tough, but quite doable. Now that I have a LAM, I don't do the intricate stuff. I'm struggling to drive it.
I do have a suggestion for the scrap practice pieces. I use muslin on the bottom and ugly fabric on top. (I don't know how I always have yards of ugly fabric). I practice on fairly large pieces.....about twin size. Once I've finished practicing, I cut it into 30 inch squares and serge the edges for a clean finish. Then donate them to a nursing home. They use these bed pads for bedridden patients. The nurses and aides are able to move a patient in the bed using the pad by grabbing the corners and lifting. Naturally, I can't supply enough for the local home, but every one helps. Even the ugly fabric pads are appreciated.