I've found a very simple way to enlarge or shrink the patterns. Just use a calculator and divide the current size into the finished size. That is the % you have to enlarge or shrink it on a regular copy machine.
For example: The pattern is 10 inches, you want it 12 inches: 12 divided by 10 = 120% to enlarge
If your current block is 12 inches, and you want it 10 inches: 10 divided by 12 = 83% to shrink it.