I am doing free form vines in big stitch on a quilt right now and have done two others some years back with interlocking circles. Love it and find it very relaxing. I use a long needle that is fairly fine but Sashiko needles work well. I use, also, a hoop, thimble and on my thumb i put a piece of Dollar store rubber glove finger tip to help pull up the thread. I think the premise is very similar to fine quilting. If you try to keep your stitches even eventually they will get smaller. Try it. It is fun and soooo much faster.