Making things larger can lose the integrity of the design but smaller should be just fine. Someone gave the correct answer earlier. Subtract the seam allowance, multiply by the percentage you want then add the seam allowance back on. Supernova is made in two halves so take that into account when you do the math. This is the first time I have been asked for Supernova smaller. My next book is totally filled with designs that werre requested by quilters. Hopefully it will be as popular as the first book. Anyway if you ever need me do post a message relating to bargello and then I receive an email. I try to get online as soon as I can. I hope to see more pictures ladies. It is so exciting for me to see the gorgeous colours that you choose.
Cheers - Eileen