Join Date: Aug 2009
Location: New South Wales, Australia
It says on their website that you make an appointment with one of their representatives and discuss it with them. I'd imagine that would be a good idea if you're confused, they'll be able to tell you exactly what you need to do.
It seems, although I could be wrong, that these saddles have a range of measurements you can choose from and then the saddle is made, rather than the truly "custom" where a saddler builds a saddle to fit your horse and you.