I have made four t-shirt quilts. the first one, I used fusible interfacing. It made the quilt very heavy. It also gummed up my sewing machine and needle. A friend told me that she made her t-shirt quilts by using the back portion of the t-shirt as a stabilizer. This has worked fairly well for me. There is a little stretching, so have to be careful when sewing the sashes. There are different types of fusible interfacing, so if you take this route, try several. Also, after I finished making the t-shirt quilts, I made a rag quilt with the bottom of the t-shirts that were cut off. experiment with different fusing, or try one without to see which works best for you. I also used stitch in the ditch to bring all layers together.