Velcro wedge to reduce seat size about 2cm (1/2-3/4"). It has a bit of cushion as well.
One of the great features of Ghost saddles is that since the seat is removable, it's possible to change the shape and size of the seat for the rider. Ghost makes a nice velcro wedge to reduce the seat about 1/2" - 3/4" of an inch. It's cushy as well. I also have some homemade wool felt pieces I make that can do the job as well as have addition features for growing/changing riders. They're two pieces, one 1/2", one 1/4" that can be used together or separately for 1/4" incremental changes. Great for people who change weight through the year or growing kids or also people who share saddles.
If you're between seat sizes, using seat reducers, pommel bolster, and a seat saver can all have an effect and the seat reducers and bolster also have a small effect on creating a deeper seat - see the pic with the felt reducers.
A thickness of 1cm is standard and provides a close contact feel for the rider.
The thicker 2cm inserts are more often used for riders who are above 175lbs or when the horse is lacking topline and needs additional protection due to a prominent spine.
If you are unsure which saddle pad style you have, a Universal pad compared to a Shaped pad cut specifically to fit your saddle's model, please feel free to contact me and so we can best determine which option to select from the drop down menu.