My trick for matching several points coming together in the center (like LeMoyne Star, Kaliedescope blocks and even pinwheels) is when joining the units where all those points meet:
Peircing the points with a pin
Glue basting the critical point
Start sewing from the center where all those points meet, sew to the edge (unless I am doing a set in seam like in Lemoyne Star), remove the piece, ensure those critical points did indeed meet the way I expected/wanted them to, flip it and sew the other side, again starting from the center.
This is a trick I learned from Edyta Sitar's book, Scrappy Firework Quilts and it really works well. Another bonus for doing it this way is you can easily swirl that center where you have the bulk of all those seam allowances coming together.