I think Western is tougher to fit, but like was mentioned, you have a lot of padding options. I though you had the EZ Fit treeless? Just curious because I am always interested in what works/doesn’t work. We might have to look again for husband’s half-draft.
I bought a Diamond Wool pad with shims to hopefully help with bridging. I thought it might be more versatile than a regular swayback pad. If you find a Western that fits pretty well (no pinching, room in the shoulders and not too long) you can try either of these pads to possibly solve a small bridging issue.
I wouldn’t buy one without trying it on, unless you get a good deal and think you can resell it for the same price. I think the Billy Cooks tend to run wider. We have an old one and a new one, and the old one is wider. You might have to look for something labeled as “wide tree”. And I would look for a rounded skirt as opposed to a square one, due to the short back.
Keep an eye on where the end of the saddle hits the horse, too. DH’s horse got a bump on her spine because it is bridging and putting too much pressure there (bridging + saddle too long?), but a square skirt can also dig into loins even if the saddle otherwise fits well.