Quilting does shrink the fabric. Unequally dense quilting results in unequal shrinking. So increase the quilting.
As to blocking: First off-I do art quilts and they are small enough to fit on the tile floor in the spare bathroom. I do the blocking after the quilting is completed and before binding. It helps remove dirt, marking, threads & animal hair/lint as well as relaxing the fabric and quilting. I fill the bathtub and emmerse the quilt for about 1/2 hour. I lay old towels on the tile floor. The I take the quilt out and squeese (do not wring) out the water. Then roll it in a towel and walk all over it. Then lay it on the towels, patting it into place. I do not try to stretch or shrink, just let it be what it wants with some patting. I put a fan on it so it'll dry in a day and close the doors to keep the cats out-they always like fresh laundry. When it's dry I trim the edges to square it up.