Sweet! The Souverans look very nice in Green/Black. Re: EF nibs, I don't think
Nibmeiester Richard Binder is too impressived with Pelikan EF nibs. If you buy a nib from him, he'll make sure it writes like melted butter on a hot pan (or a healthier option - ice cubes on a skating rink) before it's sent to you.
I used to take notes with a Souveran 600 green stripe every day, but its duties have largely been taken over by a much cheaper, but just as good pen - Faber Castell Ambition.
What inks are you using? I'm going through a phase of MB British Racing Green at the moment
The Souveran is filled with Pelikan Black though...