Soo, I got my mustang mare back from saddle training this month, and we don't have a saddle just for her yet. To my somewhat novice eye, the dressage saddle that we have for our warmblood mare appears to fit her relatively well. The only problem is, when I'm riding her with this saddle I feel as though my lateral stability is pretty iffy. I'm tightening the girth as much as I dare, but while riding I still feel as though the saddle is constantly trying to slip to one side or the other.
I've attached photos of our mare with and without the saddle. What do you think from what you can see? Is the fit passable enough to last until the professional saddle fitter can come out? Is there anything you can see about the saddle fit that would make it more likely to slip and slide laterally?