I just recently got a new Wintec dressage saddle and changed the gullet to one that is the next size more narrow. After taking the saddle off today and seeing the sweat pattern left, I'm wondering if I should go back to the one I originally had, which was the one step wider?
I'm concerned because I used the gauge that comes with the saddle for measuring but seeing the sweat pattern sure makes me wonder.
I don't really know much about saddle fit, but your horse looks like she is very bum high so maybe that is causing the saddle to sit wrong, Maybe a withers pad would help. You should post some pics of your horse with the saddle on, you can get some really good advice that way.
You know...if it makes you feel better I use to ride my horse in a saddle too small. I used the gauge thing too! I was at a wide but I changed it to the extra wide and have had no problems since...might wanna play around with it. Sale that gullet or save it for a horse you may get later on..what size do you need anyways? I have all the gullets.