Use a size 14 needle and shorten your stitch length and it should tear away fine. I usually use 20 copy paper and I've never had a problem tearing away. Cut off a little corner that you aren't using and practice sewing two pieces of fabric onto it. See if it tears away okay, if not shorten the stitch length. If it tears too easily, lengthen you stitch. Good luck, looks like a lot of fun. Are you going to do smaller ones around it or at least on the corners?