I just finished a t-shirt quilt. There was a wide variety of logo sizes from pocket-patch to full back. I also had too many shirts to make each one the same size with framing, so it had to be every shirt sewed to another. Here are things I learned.....
1 - stabilize everything with iron-on pellon
2 - really think about the shirts you have in contrast to the multitude of tips videos you will watch first. Yours may not be the same, so the tips are not applicable
3 - do NOT cut anything until you are ready to sew
4 - graph paper is your friend
5 - it can be a lot of work but the end product is worth every bead of sweat
Show us pictures when you're done!