I agree with all that has been said already. If the piece is for your own enjoyment and not for vintage value, I would certainly finish it so that you can take it out to enjoy. It will stabilize it. But my theory is that quilting should "be consistent". If this was made about 1900, it would not have been machine quilted, especially pantograph. Too, the creator of this did the piecing by hand so the quilting should be, too. Of course, I am a hand quilter most of the time (I do some simple machine quilting or if it will get rough use) but it really bothers me to see something that should have been hand quilted "scribbled on" with something that doesn't highlight the piecing. Why would anyone spend hours embroidering a quilt and then not follow through by machine quilting? If this is for your own enjoyment, I encourage you to finish it and do it by hand. I enjoy doing that as I can get acquainted with the original seamstress. You have then put a part of yourself into making the quilt.