A tip I use when PP...start and stop the stitch line a few stitches past the line (into the seam allowance area if necessary). Sometimes, especially if I am using triangle papers (Thangles for instance) I will chain piece them and cut them apart later. This seems to work well for me. I also shorten my stitch length. I often will fold the papers on the stitch line (from outer seams inwards) then tear away (I use copier paper and don't have any issue with pulling the papers).