Hm, I don't go by any recommendations - instead, I go by what looks good to me. Trial and error on a practice piece. My problem is that I sometimes forget what settings I chose, so it is important that I write them down until the project is finished.
What I do know is that the regular stitch length in piecing is too tight for me. Usually I sew on setting 2.5 and quilt no less than setting 3.0 - even that might "feel" too tight.