Should We Go Treeless?

Because my mare Lyric has such a wide back and low withers, I am having a problem finding a saddle to fit her. All of the saddles I own are too narrow--even the one I used on my Clydesdale X Freya. So I have been researching different types of treeless saddles and trying to decide if a treeless will be comfortable and safe for both of us. There are several types of treeless saddles on the market. Some are very substantial and much like a traditional saddle, while others are more like a bareback pad.