Saddling the Downhill Sausage. How?

Ok, so the mare isn’t obviously downhill, but I can’t make anything fit her. I see you tall western type riding horses like this, so how do you saddle them?

The horse:

She is a 7 year old 14.2 paint thing. Withers and croup are level, but the withers are there only because you know horses have 'em, not because they stick up a whole lot on this horse for you to see. Round back, dents in at her spine. Also, I think she’s probably wide through the ribs and narrows near her elbow.

The saddles tried. Ever’ last one of 'em raises up behind. Check the saddles and combinations:

Full QH bars MacPherson.

MacPherson with a riser pad in front.

An old Crosby AGA grand prix-- narrow by modern Standards, but not too bad on this little horse. I can still see the cantle rising off her back.

Best so far, kinda/sorta is a Tucker saddle-- big and rectangular. I still feel like I might fall over her head by accident.

This horse doesn’t look “beyond normal limits” weird in comparison to other stocky little western things, so what are you guys doing equipment wise?

Do you have a picture?

I have two beer kegs, or propane tanks, to saddle.
You pretty much can’t use a Wintec english saddle, even with the widest gullet.
My mares’ problem is where the stirrup leathers are threaded through the saddle tree. The tree is narrowest there, and I get dry spots there.
The only solution that sort of works, is to wedge the front of the saddle up, being careful not to wedge the narrow part of the saddle.

Oh, and with those wide ribs and non-withers, I have to cinch the poor girls pretty tight. I have to take them for short rides a few times before we go out all day, and I use a pure mohair or alpaca cinch to prevent galling.

I have been using a flex tree on my mom’s sofa-with-legs.