The deep seat model GP is the same 18" on the horse whether 16" or 17"' model are chosen. These saddles are light, the shape in the tree. There are no stuffed panels. they come with their own ProTecTOR pad as pictured. The No-Pinch Twist tree allows you to use it on an Arab, to a T/bred to a warm blood. This tree was designed for a Frisian. the GP has a sweat flap attached to the outer flap with a 3 positions billet rigging so you can adjust where the saddle sit on you the horse.