I have this pattern and have made several quilts from it. I didn't have any problems with seam allowance, so I guess my normal "scant" was same as what this pattern needed. It's pretty easy as you sew things into sections and then sew the sections together. Just keep checking so that your sections are ending up with what you need. I don't think the directions always give those dimensions, but it's not hard to figure out if you are piecing some stuff together, than need to sew that group to another that is 4.5" long. I reversed some of the pattern to get dinos facing different directions.