On a conventional saddle no, but there are saddles that allows small adjustments for a better fit.
The seat of a saddle is the area that you sit on. In English it is between the cantle and the pommel. In Western it is between the cantle and the horn.
Saddle seat is a type of English riding that involves a high-stepping horse, and the rider has his/her legs farther out in front than in most English saddles. Western is a type of riding where the saddle has a horn, and is deeper and more secure than an English saddle. Western riders do not jump.
You can jump in a saddle seat saddle the same way that you could jump in a western saddle or bareback. However, it will be difficult because the balance in a saddle seat saddle is different from that in a hunt seat saddle. With a saddle seat saddle, your weight is further back, and the stirrups are much longer. Also, saddle seat saddles lack knee rolls. If you are going over high jumps, it will be very hard to keep your balance in a saddle seat saddle.
A saddle seat is a concave seat, occaisonally with a ridge in the front, similar to that of a horse's saddle, found on a Windsor chair.
The name of the seat is called a saddle
English pleasure is a generic term for what is more commonly referred to as Saddle Seat riding.
That would be called a saddle
A cutback saddle is used in saddle seat riding.
For a western saddle most pads will be about the same size unless it's for a pony saddle, which will be much smaller. English saddle pads can vary significantly. Since there are different types of English saddles the pads will correspond with their individual shapes. A dressage saddle will have a dressage pad, likewise hunt seat, saddle seat (with a 3 or 4 inch cutback). Whatever the size or shape, make sure that the pad is thick enough that it protects your horse's back and that it fits right so it won't slip or rub.
The seat of a saddle
The seat in which you sit on when on a horses back is called a saddle. The front part of a saddle is called a pommel and the back part of a saddle is called a cantle. Here is a basic saddle the stirrups are not on it at the moment. They are above the saddle not yet attatched.
I was told you shouldn't oil the seat of a saddle because it will make it slippery when you ride.