I am new here - if this is old please overlook. I make lots of changes to patterns to get them to fit. I had a role of the blue freezer pressn seal (heavier than the clear) that I stuck to my pattern piece in various places and drew in my changes with a sharpie marker. I was able to then trace the pattern with the changes I desired, remove the pressn seal if I wished and not ruin my original pattern with marks. I did this on my traced muslin also to sketch in facings that were then easy to trace when I had them drawn as I desired. I had to share this as this would be great with childrens patterns that you want to keep the sizes intact but might be hard to see the sizes in areas to trace your copy. It would also be great in areas where you want to add length or width to the pattern itself so there won't be oops moments if you forget sometimes.