Well I googled it and apparently the twist is the narrowest portion of the seat, located just behind the pommel.
I wouldn't worry about it.
I'm not good with makes of saddle I couldn't even tell you what mine is.
When I needed a saddle I borrowed a few from a local tack shop and tried them for fit on my horse then rode in them untill I found the one that suited us both.
Maybe you can find a place that would let you borrow a few to try before you buy like I did.
Sorry I couldn't be much help.
EDIT: thought this link might interest you.
Saddle Fitting