I have always used sharps and buy my needles from this same guy. Today he said he had recently talked to a lady that said she only used ball points. I doubted him but said I would try them ... probably on a practice piece though.
So the picture with the Red thread is the "top" of a practice piece ... the one with the White thread is the "back". (Used different colors to check tension). Looking at the fabric again, I don't see spaces on the back but the area where the needle went in, the "indention" looks deeper than on the top. Never really noticed this before. I just think my top stitches look odd. Maybe it's just me. LOL