CNC routing a stack of laminate - GIF

[Toolmaker51]

Generally, carbide milling cutters are slightly sharper than HSS, partly because higher density. Solid D-bits are available in either material, larger diameters are cemented (brazed).

D-bits are de rigueur for engraving. depending on diameter-material-depth. RPMs can exceed 24k. They are typically tapered and ball end.
A D-bit is technically 100% clearance, providing straightest, shortest chip ejection compared to helical, but restricts maximum depths. As depth increases, the need of efficient chip ejection increases at greater ratio because volume and heat retention. Thermo-sets are less problematic than thermo-plastics.

The balance issue is counteracted by mass in the drive, especially round belt types of full size pantographs.
I'd suspect armature and distance between bearings is good for any bits your spindle (and collets) accommodate.