Hmm, I've only got one pen that uses a Schmidt nib, a Muji round aluminium fountain pen (the long/full-sized one that looks a bit like an X-Acto knife, not the short pocket pen). The nib size on this pen is a (Western) fine, with a pretty standard line width, about the same as a Lamy fine.
Going by this sample of one, I'd describe this nib as...
- Very average in terms of wetness. I'd rate it an exact 5 on a wetness scale of 1-10.
- Has a significant amount of feedback, but not scratchy at all - it feels, and also sounds, rather pencil-like in writing. Imagine, say, a Platinum 3776 Century nib, but much stiffer, and a little dryer.
- Very stiff, rigid.
- Reliable writing, no skips or hard starts ever.
- Apparently Schmidt also makes inner caps to go with their nib units; I'm not entirely sure if the Muji pen's inner cap is the matching one supplied by Schmidt or not, but if it is, I can say that it seals particularly well. This Muji pen is very resistant to drying out, at least as much so as the Platinum Balance/Cool, for example.
The Muji pen I have is a cartridge converter pen. Due to lack of experience, I cannot comment on the buffering capacity of Schmidt nib feeds, or whether these nibs will be suitable for use in eyedropper pens.