Whenever I have any block with many converging seams in the center (Pinwheel, Lemoyne Star, Kaleidoscope, etc) I do not stitch my final seam edge to edge all the way across. Instead I start at the center, stitch to the edge, remove the block, flip it and then do the other side. This technique offers several advantages.
1. It allows you to start at the multiple seam intersection so no need to remove a few stitches to swirl the center
2. It gives you better control of how that center comes together because you are starting there so those center points all line up correctly without any getting chopped or off kilter
3. It allows you to press that center seam in two different directions to help avoid bulk and lumpy build up.
Joining the units of block this way greatly improves accuracy and greatly reduces frustration. So worth the few extra seconds it takes to sew the seam in two passes instead of one.
Edyta Sitar recommends doing this. You can google her tutes for 8 pointed (Lemoyne) stars to get a visual of what I am talking about. She also describes the technique with lots of photos in many of her books. I learned it from the Scrappy Fireworks book.