It's a great pen!
After several years of ownership, this week I discovered that I can trade the default TWSBI nib for the Goulet nibs. It opened up a lot of possibility with this pen.
I've been doing this for nearly a year, with my two Vac 700's. However, all of my Goulet nibs (EF, F, M, B, 1.1, 1.5) write much wetter than the same nibs made by TWSBI. I only have the F, M, and B Vac 700 nibs, but the difference is striking.
I use it to my advantage when I want a very wet nib for a dry ink, or, especially when I want a very wet 1.5 mm nib for greeting cards, addressing Christmas cards, etc. I cannot tell any difference between the nibs visually, holding them together, nesting together, examination of nib and slit under magnification, etc. The only thing that I can figure is that the profile of the feed leaves a little bit more gap with the Goulet nibs than it does with the TWSBI nibs, there could be a difference in curvature that I can't measure. Both nibs are made by JoWo in Germany, look identical, extremely smooth writing.
I'm not complaining, as I said sometimes that is exactly what I want, to make the Vac-700 a wetter writer. And, I've swapped nibs with the Vac-700 inked with no problems (except inky fingers).
Has anyone else noticed this?