Nibs from the Mini or Classic swap into the Eco, you have to wiggle them out of the feed housing, which is tight. The 5X0 nibs do not fit in the Eco (I tried.)
The G nib I'm using is heavily modified to fit the eco.
Woulda been nice for pen hackers if TWSBI would have gone with the #6 size nibs; we'd have tons of options for swapping then. As it is we are mostly limited to TWSBI nibs (which makes more sense for TWSBI of course.) The #5 nibs aren't remotely proprietary either, it's just that #6 nibs are more plentiful.
Bookmarks