Notes from author
This is the build i'm currently using on ps3.
The longsword is fast, don't take a lot of stamina to use, you can buff it with resin, it also has a really cool moveset. The one handed r1 is pure gold, two handed r2 is powerful and has a wide swing etc.
The scimitar in the left hand allows you to parry and has a wide swing too. It's really quick and can be very useful while using the zwei. And when you land a parry you can get a free hit if your opponent has enough poise.
The zwei is a good back up weapon, your opponent won't expect you to use such a weapon. When rolling you can switch and imediately go for a r2. Rolling attack of the zwei has good range too.
You can switch to it for parries if you're not confident with the left hand parry free hit.
Everything is about to use the right weapon at the right moment and use the right attacks.
I'm having a lot of fun pvping with it.
Enjoy