I am saddened to report that using a high precision silicon nitride bearing in a trackball is absolutely decadent to the touch, oil-on-glass smooth with the perfect slight hint of heft in the motion, looks absolutely amazing and does not work well at all.
Update! You just have to let it oxidize slightly, for a day! It works perfectly now that the shine has dulled just a bit. This is great.
Verdict: you should replace your trackball with a silicon nitride bearing machined to micron precision. You will definitely not regret replacing your trackball with a silicon nitride bearing machined to micron precision.