I brought an Apple PowerBook G4 back in 2005, and one of the standard system configs allowed you to calibrate the subpixel rendering parameters of fonts for the built-in display, as well as any external displays. It remembers each external display by serial model so that it could load the correct calibration profile for that particular display each time it's plugged in. I must have obsessively calibrated each of my displays at least ten times.

Was this feature removed from OSX? Or did OP try it already and it didn't help much? Honest question here; I haven't touched a mac in over a decade.