There is small fix you need to do for you Churn Dash blocks. As I was making mine yesterday I realized the HST blocks finish at 4 1/4", not 4 1/2". So here is the simple fix we came up with.
Here is how your pieces will looks following the instructions. The center square and double rectangles are 4 1/2" square and the HST squares are 4 1/4".
All you need to do is trim the center square and the four double rectangle blocks to 4 1/4". Then you can assemble the quilt block with no problems.
When trimming the double rectangle block take 1/8" off each side so the center seam stays in the center.
Then trim 1/4" off the end.
Your pieces will now all be 4 1/4" square and sew together nicely.
The finally block will measure 11 3/4" square.