Take the time to visit Youtube and see how Sara uses the ruler. Her approach is a little different than mine. I add a full round of 4 logs and then trim, but Sara likes to add 2 strips of half a round, trim then add the remaining 2 strips of the round for the final trim. Both methods work...watch and choose your own. https://www.youtube.com/results?search_query=heirloom+creations+curvy+log+cabin
Here is my newest Curvy Log Cabin quilt. I made the quilt in a week, another reason I love my trim tools because there is no precutting, no math and no measuring thus eliminating hours of prep work before starting to sew when you use the tools.
I used Tonga Treats Cabana 2-1/2" precut strips by Timeless Treasures. The setting for the quilt is the traditional straight furrows setting. The curved blocks in this setting look like waves gently breaking on the shore with the light rows water and sand and the dark rows are the seaweed.