Thanks, everyone, for the great saddle feedback!
The tip about the wider twist makes a lot of sense–I hadn’t thought about that before but it makes sense now I’ve read your post, Pintopiaffe. I’ve also thought of a treeless–I rode once in a treeless trail saddle and fell in love with love with it.
Most of my back pain comes from an old ruptured disc injury that has gotten better over the years but just won’t let me move certain ways or get in certain positions. Sometimes my lower back just hurts. Most of the time riding makes it feel a lot better, but only if I can really soften and sort of round my back and relax. I think a lot about my position when I’m riding, but I think I really need to concentrate on “Is this comfortable?” rather than “Is this ‘correct’?”
The only Passier I’ve tried was an old narrow one (too narrow for both me and my horse). But I’ve looked at some of the new ones, and the Optimum does look and sound like it might be comfortable for womanly sized riders, even ones with short legs, like me.
I love your comment about the hourglass figure with all the sand at the bottom, Everyequine! Is it Louis L’Amour whose characters admire people who have “sand”–as in “true grit”? 
