Has anyone tried one of these Vindolanda pens made from 2000 year old oak dug up at the archaeological site in northeast England? I think its a cartridge converter pen. https://www.vindolanda.com/shop/vindolanda-wood-ink-pen From a Reddit post I found it looks like a F/M-ish nib. https://www.reddit.com/r/fountainpens/comments/csjvti/my_first_fountain_pen_made_by_david_wayper_out_of/