The good thing is english and dressage saddles that will fit are fairly easy to find. A good quality MW, W, XW..., or a 33 cm and larger saddle tree will typically fit. I ride in both a 35 (thinner more modern Percheron) and a 37 (mutton withered curvy Percheron mare). The problem is finding a good quality girth to match. I use a 40" and 44" on long billets. I have a bridle from Draft Tack that is fairly good quality buy the reins were way too short. You need 110-120" reins. Not the normal 90".