|I prefer my neckline facings for a top or tee in a woven or knit fabric without shoulder seams, this to prevent the unnecessary thickness at the shoulder seams. There is no need to double up the seam allowances at the shoulders.
Start with tracing the front and back pattern of your neckline, join the shoulder seams and trace this new neckline for a facing pattern. I add a seam at the centre back and cut the front centre part at the fold, if you use a half part pattern. If you want to use a single layout duplicate the other half pattern. I mark the shoulder stitch line so it is easy to see where the facing meets the shoulder.