It's a beautiful quilt! I wonder if the quilting lines were radiating out from the center, if it would blend better. I know on that background fabric, there are lines that radiate out from the center. Could you follow those lines? It looks like that's the way your started it on the light colored section.
I like to use the same quilting lines that you've used, too -- the long lines that flip at the edge of the design. They are a great filler.