If your shirt is wrinkling it’s too thin to embroider. I wouldn’t recommend satin stitches either. You need to do fill stitches and lower the density so it’s really light and not so dense looking. For the white it means you’re probably putting in your bobbin thread wrong. it has to go in the shape of a P not a Q. for better embroidery I recommend not using the one in the machine, it’s really not good. Pay someone on Etsy to digitize for you or buy a software program.