I have made a couple rag quilts that required the 4.5" squares of batting. I use a 60mm cutter all the time and like it better than the 45mm. When I made my rag quilt, I used left ofer pieces of batting which seemed easier to cut that from a large piece. Plus I was able to make my pile smaller of left over batts from quilts. I also found that if I cut 50 or so at a time and then took a break that it did not seem like such a big project. Good luck and I'm sure your grandkids will love them.