Why not make a 4 in scrappy quilt, just using the 4 inches as is. I saw a quilt in a recent magazine with just 4 inch squares in first row as is, the second row they cut the "only first" 4 inch sq in half and the rest were regular 4 inch squares, and then the third row goes back to regular 4 inch squares sewen in row again. They said this helps, because the seams don't meet in the corners so help where there might be bulk.
I have been thinking of sewing a 4 inch square row, then a 2 1/2 inch strips row in random lenghts, then a 4 inch square again and etc. Good luck on what ever you decide.
IdahoSandy