Absolutely the worst I’ve ever sat in are the Wintec Pro, and Isabellas, both the Wintec and Bates version.
I also don’t do very well in Stubbens.
I tried the Ideal Susannah, which was very comfortable. I ended up with a used Frank Baines Elegance, which horse and I both love, love love, yet found the Frank Baines Reflex to be quite uncomfortable.
I also love my County Drespi, which is a really good choice for a petite rider, as it has short flaps which are also adjustable from dressage to jumping position. You can often find them used in smaller seat sizes pretty inexpensively, yet my daughter is miserable in it unless she adjusts the flaps to the forward jumping position and she’s built very similar to me.
Is there a saddle fitter anywhere near your area or one you can do a telephone consultation with? The good ones can often tell you a model to look into if they know what saddles you’ve found comfortable in the past.
I feel your pain OP, its very hard to find a dressage saddle that’s a good fit for a petite rider and horse. I’d gladly send you my Drespri to try, but its the only one we have that fits DD’s horse. And it has a 16" seat!