No, Organ needles have the same size upper part asany other 15x1 needle, which is the needle system you want for your Necchi. You definitely don't want industrial needles. I've never needed a jeans needle or other heavy needle to sew the bowl cozys. I've sewn them on several of my machines and have always used a 15x1 sharp needle in a size 11, or I'll go to a 14 if things get too thick. I buy Organ needles size 11 in bulk so I use this size for 90% of my sewing. Schmetz sharp needles are called Microtex.
Cari