I think your cinch is the right size. If you go any bigger than it interferes with the vein that's on the barrel of the horse. My Vet told me 80% of people have to big of a cinch. You don't base the cinch length on the amount of leather left. I would put the Right side up one hole, the saddle hasn't been tightened and she probably hasn't sucked in yet since you probably just threw the saddle on to size her, so that's why it looks so small on her. When you do up the cinch, make sure to walk her a bit, tighten it, walk her a bit more than tighten it again. You can also tickle her tummy to help her suck in. Horses suck in as we ride so the cinch will get looser. I'm not saying cut of her circulation tight though. In the pictures, It's in the right position (from what I've been taught). So go up one hole on the right side to account for her sucking in and you having to tighten it more. (This is all the advise I got from my vet.) If you want to be sure you have the right size, here is a site that tells you how to measure. How to Measure Your Horse's Girth
I agree that the saddle didn't fit. There was way to much Space on the bottom of the saddle to the horse. Saddle hunting is a difficult task. I agree with trying to find a a Billy cook or something, better the brand, the better the fit. Can you haul your horse to the tack store and try on every saddle in the store? Once you find one that fits her, you can order the seat size you need or look for it used. Every saddle maker is different and one gullet size won't be the same in another brand :(. CONFUSING AND HARD. I've been here before just like you. You could try these templates to give you a start. Trace them onto cardboard and cut them out and place them on the horse. http://lib.store.yahoo.net/lib/thesa...llet+Templates
I've uploaded a couple of pics. One shows you how you need to pull your pad up into your saddle or it's going to put to much pressure on the withers. I think your saddle is placed about an inch or two, to far back, but it really isn't all that bad.
Good Luck! And Welcome to WESTERN!