Great review. Yes, I would expect an XF to have some feedback. You could smooth it out a bit by tracing some figure 8's on a brown paper bag. If that doesn't work, there's micromesh. I don't remember when Twisbi started using Jowo nibs, but they definitely do now. Which leads to an interesting thing in that although Twisbi is an Asian company - Taiwanese specifically - they use German nibs which run wider than Japanese nibs. XF Jowo = F Pilot/Platinum/Sailor
The size comparison is helpful! Thank you gents! That is one thing that I really like about my safari is that the nibs can be changed out so easily and economically. Part of the intrigue of the 580ALR to me, on the other hand for $10 more you could get a whole new pen in the eco. Lots of options . Or I could go the vintage route! John you warned me about the nib rabbit hole!I smoothed it as best I could. it's generally not an issue and I only feel it occasionally.
and I'm not comparing it against Japanese nibs, but other German/American nibs. much like my experience with Lamy Safari grade nibs.