Over the last year, I have been practicing grinding nibs. I bought Chinese pens and nibs in bulk and have gone through a few dozen of them to practice and I am quite happy with my recent results. However, I have not ground any expensive nibs so far, my logic being that even if I like the grind, it's not worth it to remove the tipping material. Am I right on this? I have two Souverän M400 nibs -- one M and one B -- and I really want to switch out one of them for a stub nib. I am trying to decide if I should take a crack at it or keep looking for a stub nib at a good price or a trade? Thoughts and suggestions?