You can actually do that by hand and make the stitching look like machine stitching, without any spaces in between. I've done it. They aren't big areas, so that's what I'd do. When it's finished, you won't be able to find any differences between what was done by hand and what was done by machine, if you are careful. Start off with half of the length of thread on one side of the quilt and half on the other side with the needle on it (no knots on either end). Make the first stitch the correct length (to match those already machine stitched), and you end up with both lengths of thread on one side of the quilt. Now switch the needle to the other length of thread and pass it through to the other side of the quilt through the same hole the first thread is hanging by. Continue in this manner, following the mark you made for the quilting, keeping the stitches very uniform in length. The stitches don't interlock between the layers like machine stitches do, but they pass each other figure eight style between the layers. Hope this makes sense.