I have made several tshirt quilts. After applying interfacing, my designs are cut with 1-inch allowance around each design. Sometimes I have to make it less to fit the design into the block. I put sashing around each design to compliment the design. I have even taken apart old clothing the muse as the sashing for some designs. I do not use the same sashing around every design. I often put 2 or even 3'designs into one block if I have very small designs, and I orient them as needed - horizontally, vertically, and even diagonally. Each completed block is cut to a 15-inch square. I need at least 16 15-inch squares to make a decent sized quilt. I usually have 20 squares, then I add a 4-inch border. When it is time to arrange the blocks, I lay everything out on the floor and move the blocks around until I have am pleased with the arrangement. I love to make tshirt quilts. It is so much fun to watch the recipient find old favorites or remember why they got a particular shirt. Have fun and don't stress making the quilt.