I was commissioned to complete a quilt for a woman in town. This delighful woman quilted before she started golfing. She had completed a couple of quilts for her daughter many years ago. She also had hand pieced 23 blocks in the early 80's. Stored in a Pizza Hut box, she asked me to make a quilt for her son. It took me a while to figure out how to put them together, mainly because they varied in size so I wasn't going to be able to just sash and go without loosing a portion of a number of the blocks. I'm sharing my process just in case you find yourself in my situation one day.
The blocks varied in size from about 11 inches to 12 1/2 inches. In order to use all of the blocks in close to their original size, I decided to make the blocks the center of a square in a square and then trim the new blocks to the same size. This was my process.
With the largest blocks at 12 1/2 inches, set on point, the with of the new block at a minimum would be 17.67 inches (remember the pathagaream theorem?). So I needed to cut setting trianges large enough to cut down. I cut 17 inch squares out of muslin diagonally twice to make these trianges. I then sewed theses trianges to each side of each block. I trimed the edges off of each side as shown here. You can see that I didn't loose any of the block to excessive trimming.