In this instance I would make the several strip blocks and wash them to check for shrinkage. I have done a number of signature quilts and found that this was a better way. For me the signatures were the most important part of the quilt. After you know how much if any shrinkage you will have you can make your blocks or the entire top and then have the signatures added. Then heat set the signatures well. It is better to lose a little than the whole quilt top.