What I worked out with my first post.
When I put the blocks/rows together with a sashing (Quilt As You Go) Instead of doing the usual 2" folded in-half for one side and 1" on the other. (I usually put the folded on the front side) I found that if I cut the sashing to be 1 3/4" and fold it in half for the front, and 1" on the back of the quilt. (I put them together the regular way (in joining the blocks/rows - sewing the two sashing strips on then attaching the next block or row).
I use quarter inch seams except for sewing down the folded side. I sew the folded side down with a scant 1/8" right on the edge of the folded side, and it ends up in exactly in the same place on the back (1" inch) side - right inside the sashing a scant 1/8". The sashing looks exactly the same size front and back with the showing seam exactly the same on both sides - fully on the sashing and not on the quilt block.
The blocks/rows meet together with no gaps between them and the sashing lays completely flat with no bunching on one side or the other when sewing down the folded side to finish because they match on both sides of the quilt.