Yes, longer stitch length; try doing your topstitching a tad closer to the inside (so not going through so many layers); try a walking foot if you have one or a teflon foot if you have the PUL on the topside. I'd put your tension back to your original setting. You might also lessen your presser foot pressure a tad as well if you have that option. And the larger needle wouldn't be a bad idea either.