Just a note here. You don't sew through the paper when doing EPP. Just catch the corners as you fold the seam allowance over whatever template you use. When you join the pieces together you just catch the fold with a whip stitch or ladder stitch. There is no need to sew to the paper. Paper can be reused several times before it wears out.
Using mylar is a good? and will be looking for an answer to this.
peace