Out here in WA, we have saddle fitters associated with horse stores, who will have a chat to you on the phone or via email, and then bring a variety of models to your place that might work to try on your horse, and then narrow it down that way. It's not actually very expensive to do that, and this process has resulted in my best saddle fit ever, to a broad-backed big-shouldered horse and a rider with long femurs. We've never been more comfortable...only wish I'd done this before. Riding in an Ascot Romana AP, by the way, which was one of the saddles she thought would work for those factors, and then she adjusted the gullet and stuffing to make the fit perfect.
SueC is time travelling.