You do have a nice quilt in the works.
And I agree, the brown really makes those blocks pop, far better than the green did.
Unfortunate that you have now realized the non-washing.
I saw your photo on the other thread.
While it may cause problems, I think if you heavy quilt it, you can get it stabilized.
I wouldn't go with SITD, as that would leave the open areas more apt to show the shrinkage.
Instead head towards some sort of an all over pattern, where the stitching will cross the seam lines as well as stabilize the fabric.
However, nothing is guaranteed ..... you could do up a small sample piece and see what happens.
I'm thinking placemat or table topper size would let you see what happens with washing/drying.
Another consideration ... choose your batting accordingly.