I used iron-on stabilizer on the t-shirt quilt I made, and I think it was the right choice.
Quilting is another story. As I recall, I did SITD along the sashings, but really struggled with the t-shirt pieces themselves. I was using big blocks (because the t-shirts I was using had really big designs) and was not satisfied with the results. I sort of tried to go around the design with some meander in the blank areas. Definitely not my best work. Oh, I used regular cotton fabric for the sashing and borders.
Good luck! Chances are it will be loved, no matter how you make it.