I used shirt backs to make some blocks larger, also as a long narrow filler for a pant leg block. Because this was also a memory quilt I made a tiny t-shirt with pocket, from a t-shirt our son wore. Turned out real cute and our blocks were a lot of different sizes and the logo's from sleeves were grouped into one block.
Her younger sister is collecting her shirts for her graduation quilt. Will also make a tiny shirt for the next one.
Make sure you stabilize each pieced block as one unit.
Can't wait to see your project.