From a post where I was exploring a “mode” feature of my machine that alters speeds and accelerations. For smaller items like these earrings, you’re going to limited more by acceleration than max rate.
Set up a material test similar to that pictured below. Cheap material is fine. Bump up the square sizes a bit…8-10mm works for me. Power is relatively inconsequential for this, just need enough range to make the marking clearly visible. Run speeds from where you’re current 300mm/min to maybe 5000. Enough to get useful data. You can narrow or expand from there if needed.
You’re looking for geometric anomalies like overshoot/rebound at the corners or wiggly lines.
If you want to really dig in with tuning, you can tweak your acceleration values at $120 & $121, just save your current values before making any changes and keep notes as you go.