I have done several t-shirt quilts. My daughter and I did one for a friend of hers that does a lot with Special Olympics. First we ironed a interfacing we bought at the quilt shop, we put strips around each shirt and did borders around the quilt. Our backing was black and we had it quilted with the Olympic torch and it was just beautiful, he was one happy fellow.
Everyone says to quilt over the shirts, those t-shirts arent heavy and dont break needles, dont think she wanted to do it dont think I'd go back to her.