Bates seat sizing - tall rider?

[FabioandFreddy]

I know the Bates generally come up a bit big. I'm 5'9" and its more the leg length i'd need to worry about. Would i get away with a 17" in a Bates Isabelle Werth? I've rode in a 17.5" Bates Caprilli dressage and the seat was huge so know seat wise a 17" would be fine. Do the Isabell Werths come up big like the Caprilli's??

 

[Polotash]

I don't know if the leather Isabells are the same as the synthetics, but I rode in a friends synthetic one the other day and it was far far to straight cut to fit my 34 inch legs on so make sure you try before you buy!