I used one that Irons away for a soft finish & wash-away for a stiffer finish

Barb I have used WSS & a tear away I think since it's an ornament & u will see both sides I would use the WSS. Let's see what some of the experts say. *

sandwich the organza between two layers of WWS, one on top and one on the bottom.

I took a class at Joann Fabrics several weeks ago on FSL angels on organza. We hooped two layers of vilene(the fabric type of WSS) and then floated the piece of organza on top. The first one I made I pinned the organza down but after the first one I realized the outline stitch quickly catches the organza and the pinning was not necessary. I made 25 of the angels for gifts and they were so easy and quick to make. Hope this helps.