I've never made a t-shirt quilt but saw a beautiful one in a mini retreat that my local quilt shop conducted years ago. Like gramajo said, I feel like they are a lot prettier if the blocks are staggered in some form or fashion so they don't just line up in rows. In the picture below, the quilter at our retreat used "filler" sashing/blocks between the logos & it really was appealing to the eye. Good luck with your new venture & welcome to this board.