I find out the same way you did that the smaller needle is much better for batiks. I asked at the LQS and they all said the superior threads titanium needle.... I figured out that was a self serving recommendation and changed to the 70/10 and it made a much smaller hole. Sometimes I use a 70/8 and have very good results. the last thing I want when I take out stitching is to have the evidence ( the holes) permanently documenting my error. Unlike regular quilting cotton the holes from a larger needle do not disappear when washed.