What kind of ink/pen do you use and where do you get it???
I use speedball Super black india ink, and two different nibs. From all I know they aren’t branded, I just get them out of a little drawer! I’m not a fan of knowing sizes or whatever, I just buy what feels best at the time. I use both of these for every drawing, the bigger one for basic outlines, and the tiny little nib for hatching and details. That’s really all I can tell you as I can’t remember the numbers on the little drawer I took it from.
And I got them from an art supply store, they’re sure to have them. My advice is to just buy a couple nibs and the pen/handle they fit into and try them out and see which one you like, it’s different for everyone! I like rigid ones without a lot of give, but for instance my friend likes them super flexible and delicate. Sorry I couldn’t be more of help!