You may not be aware of how huge this question is 1st: I would like to know the different brands and what type of conformation that are made to fit?
Oh my. There are so many brands out there. Hundreds. In addition to the really big brands, there are even more smaller brands, and even mom and pop shop saddleries that may not even put a maker's mark or have a brand for their saddles.
Each brand will fit differently (there are exceptions, for example Bates and Wintec saddles are built on the same tree, so are Kent and Masters and Thorowgood, and there are many more like that).
Now we add a second dimension to that. Because within each brand, there are different tree designs for their different models, which are made to fit different conformations.
Rather than asking for a list of brands and how they fit, I think we need to narrow it down a bit. You can narrow it down by stating the price range you're comfortable with.
Since you're looking at the Wintec 500, I'm going to assume that you want to stay under $1000, or under $500, but we can probably eliminate the Ones from $1000-$5000, is that right?
Are you interested in only new saddles, or used, but newer model, or are old classic saddles in great shape also an option for you?
If you answer those questions for you, you will probably get some useful answers to your question #1.
"2nd: What brands do I need to looking into for my horses specific type of conformation?"
I'm going to assume that you want to stay under $1000, and that new, used, old doesn't matter, as long as it's a quality saddle that fits you and horse correctly.
I've had several Morgans and ride several Arabs. I also ride Friesians, so I'm familiar with the difficulty of that back.
I have often run into the bridging problem with the wide horses, and it's often not because the saddle is too straight in the panels. I've often found that it's because the gullet is the wrong shape. If the saddle is A-shaped when you look at it from the front, the tree-points just can't reach wide enough to properly cradle the withers before heading downwards, so the front ends up sitting too high up, and the center of the saddle can't sit where it should and bridges. What you want is called a "hoop-tree". It's shaped like an upside-down "U".
I am not familiar with nearly all saddle-brands. I have some that I know well and really like, so I can discuss a couple of those.
-1- Duett saddles have hoop trees and are made for horses like this. You can find them used under $1000 on eBay, but then you can't return it if it's all wrong. They cost $1300-$1500 new, then you get great service from the rep. Look up some of their saddles on eBay just to get a look at the shape of the front of the saddle, and you'll see what I mean about the hoop-tree. Look at the picture of this saddle from the front, and you'll see how that will nicely span your horses wide withers and sit lower in the front, letting the center contact the back. Duett Largo Dressage Saddle 18" Seat with 38 cm Tree | eBay
-2- I just got a custom Thorowgood. They are also made for wider horses, but not super-wide ones. I'm using mine on Arabs and Friesians. One Friesian is just too wide for it, but others are OK. It has a hoop-tree, but a pretty modest one. Fits those horses infinitely better than the Wintec I tried though. Thorowgood makes a "Cob" or "Broadback" model, for the wide flatbacked horses. It has a very wide twist that I find difficult to ride in. I have the regular tree, and it fits the hroses I ride just fine, but none of them are truly flat-backed.
-3- Thornhills are good for wide horses. I have not had one myself.
-4- I love the old German and Swiss saddles: Passier, Stubben, Kieffer, Courbette, Felsbach, Kloster Beim Schonthal. However, I have never been able to get one to fit a horse with your conformation before. They just run too narrow at the withers. I have seen some of the old Kieffer dressage saddles with a good hoop-tree.