Hiya, my 2 cents. If you have a well tuned machine (which i assume you do):

• Extrusion widths that are up to 50% larger than your nozzle diameter are beneficial, because the brim of your nozzle flattens the material against the lower layer
• Printing many keycaps at once can help the stem cool completely between layers, if heat is a problem
• Have you tuned pressure advance after swapping nozzles?