You sound a bit frustrated ..... this is definitely a time to be using Best Press!!
My avatar quilt is much the same pattern.
I made it before I knew the merits of Best Press (or even starch), and had few problems.
However, I did learn the merits of good pressing practices during the preparatory stages
and at every step along the way.
You have a beautiful quilt in the works and that alone will be worth keeping at it!