This is how I've always done hand piecing too. The back stitch just makes it a stronger seam and will hold if a stitch gets broken.
Originally Posted by Hinterland
I think your blocks are just fine as is. I use a running stitch, with a back stitch after I do a needle-full...so I guess it's every 5 or 6 stitches. I really don't know how much stronger that back stitch makes the seam, so I wouldn't worry about the blocks you already made.
Janet