The more seams in a blk the more chance it will not fit without exact 1/4 in seams in every seam. When working on a blk like this it will also depend on the weight of the fabrics. Maybe you need a scant 1/4 in seam instead of the 1/4 in.
This is a more thana beginner blk also.
Hope you get it figured out it is a great blk.
ConnieF