I did a tshirt memory quilt and was given some plaid shirts to include if possible. One plaid was especially thin, so I did fuse that one, but the others were sturdy enought. I had no problems combining fused tshirts with quilting cottons (sashings and borders) and the plaids (2nd border). I have made attic windows with the shirts being the window...shadow blocks and just squares with sashings and corner stones. I have a hard time getting motivated, but when I get started they are kind of like a puzzle!
here is a picture of the shadow quilt