I have found the fusible nylon tricot to add quite a bit of weight and thickness. Haven't tried it, but I'm wondering if MistyFuse would be better. Requires slightly different handling because MistyFuse doesn't have a paper backing (I would just use parchment paper when fusing it to the t-shirt fabric). I think it's Bearisgray who uses MistyFuse on the backs of regular quilt tops to fuse to batting. If MistyFuse would do the job, it would be a lot thinner and softer than nylon tricot.