Hi Pat,
A copy machine can be your best friend when it comes to changing the size of your motif... or paper piecing patterns as well. Measure the size of your block and the size of your motif. Then divide the block size by the motif size. This will give you the reduction percentage. For example, a 6" block and a 10" motif... 6 divided by 10 = .6 Move your decimal 2 spaces to the right & your reduction will be 60%. If the measurements were reversed, this would be the increase percentage.
Clear as mud?
Oh, I use water soluable pens for lights & tailor's chalk for darks... both wash out very easily.