John: That depends on how long until you're ready to put your shop/building up. You should be cutting your mortises by planning on the shrinkage. You can review your book, by Jack Sobon, "Build a Classic Timber Frame House" and look at the pictures on pages 88 (in the middle of the page), page 91 (lower right), and page 122. These photos show how and where to hollow out your timbers to take into account the shrinkage. I'm not sure if this will help you with the ones you've already made or not. Good luck with your project, Jim
