I would suggest to just request using t-shirts. There have been many previous post here on making t-shirt quilts and many different layouts. I used Pellon featherweight fusible on the back of the front of the t-shirt adhering it to the shirt before cutting. You really don't want to get into sweatshirts or jerseys that have obvious vents in them. Be sure to see who is going to pay for the fabric and if you are going to get any compensation. Be aware that people who are not quilters don't realize the time or cost involved.