it seems like the gullet may be wide enough for your horse but that's slightly difficult to tell without feeling where the muscle starts on either side of the spine. the saddle may need to be pushed slightly farther back to keep off your horse's shoulders which, from what i can tell in the first picture, may balance the saddle better on your horse's back so that YOU will be sitting in the center of the saddle. the panels on those wintecs tend to be very flat/straight so if your horse's back is of the same shape then you may be in luck.
i am not a saddle fitting expert so please take this with a grain of salt. :)