Again regarding the choice of pens: How does the plotter behave with a softer tip?
I'm thinking of the Tombow Fudenosuke pens - they have a wonderful soft tip, which allows for calligraphy in the hand of humans.
When used by a plotter, by changing the Z depht it would be possible to have very interesting dynamic variations, wouldn't it?
I can see how easy it would be to break the tip too, so better buying a bunch of those.