I need help choosing a saddle?

Although I completely agree with having "professional" help with saddle fitting, it will much more cost effective to bring the horse to a good tack shop (not one that only has a few saddles but one with many to choose from). I don't know how much having a pro bring many saddles out to you would cost but I would not be surprised to learn that the cost is close to what you have to spend on a saddle to begin with.

Again, thinking about cost, a synthetic is a very good option. Even used, a really nice leather one will cost more then your budget. Whatever you do, DO NOT fall into the trap of buying one of those package deals you see on ebay or even in the catalogs that sell for <$300. They look attractive but they are Asian made and the trees and the leather are of very poor quality.

Leather most certainly will stretch until it breaks, given enough pressure and/or improper care.

Also, leather or synthetic in a SADDLE will not stretch, except maybe leather stirrup fenders/straps. Synthetics do not stretch at all.

There is no part of a saddle that is going to "stretch" except for replaceable pieces like the stirrup fenders/leathers or billets/latigos. Synthetic nylon latigos/billets don't stretch much at all, and only break with a LOT of use/wear. They generally last longer than leather latigos/billets, which can stretch out of shape, crack, and break with use and even just time.

I am a saddler with 17 years experiance - there is nothing wrong with a good synthetic saddle ( I have 5 myself , 3 wintec and 2 thorowgood )

A saddle should be properly made and properly fitted . Do avoid cheap non - branded saddles . A second hand wintec with a bit of wear and tear will be 100% better than a brand new leather saddle that is cheap and of dubious origin.