I've been trying to fit a saddle to my downward built mare. She's currently going in an xwide saddle. It fits ok when she's just standing there, but when I'm riding, it really digs into her shoulders and slides forward..... I've tried a reverse wedge, but it's such a pain to use and it caused bridging. I've tried a front riser pad, but it just made the saddle tighter. I know she could use an xxw saddle, but what can I use to help the level her out? Suggestions??