This is how I made a T shirt throw. I didn't look up any instructions. First, I determined the T shirts I wanted to use. Second, I determined which logo (or whatever is on the t shirt) was the largest. Third, if it was larger than I wanted to make my block, I decide how I could use it and not mess up the logo or choose another one. Fourth, considering the largest of the logos, I measured it out for a square, leaving some of t shirt only for "framing". Fifth, I cut cotton muslin the size of the block of the t shirt, (because t-shirts are not usually on grain and also stretch) Putting the t-shirt under the square of muslin, I then cut the t-shirt to fit the muslin, and pinned it just enough to keep things together. Even one or two pins in the center of things. If I remember correctly, I put a narrow sashing between them. The for backing, I used a "sweat shirt", cut it in such a manner as to have the logo either in the center or top half, or bottom half. I pillow cased it. and Wa La T-shirt throw.
I did this for an auction for a private school to raise funds. I had one t shirt for each grade up to the ninth, 10th, 11, 12, had not happened yet. At the auction it sold for $400. Remember this was a fund raiser for a school. There was room on the back to put the other three years as they happened. Good Luck. I hope you find some clue herein to help. I'd appreciate an update. Silvia