What type of dressage saddle should I buy?

ponyperson92 asked:

I am in search of a dressage saddle for my new horse since my old saddle does not fit her, She has a medium wide gullet, she is around 15.2hh and weighs about 827 lbs. She is a thoroughbred type appaloosa. I am 5'1" with a long femur and usually ride in a 16- 16.5" saddle.

How do I size a saddle to fit my horse?

bethany p asked:

I always thought you purchased a saddle to fit yourself and for comfort for you. Anyway, I keep seeing all these descriptions of saddles and "gullet" measurements. So I thought maybe this is why I can't get a saddle to stay on my horse, who is EXTREMELY fat. Exactly what is the gullet of a saddle and should I have a wide one or a narrow one. Thanks for any help.