I have a 7 yo 9900 of which I just changed over to PiezoPro. The Orange channel is dead and the yellow channel has 1 tiny clogged nozzle. I am running 8 inks plus GO and would not mind adding that last ink, VL warm. I am also concerned about the future availability of heads for the 9900 so I am willing to buy a replacement head now. However the service tech says there MIGHT be an issue with the uni/ bilateral calibration because there are no color inks in the printer and he’s not sure if that calibration requires color. My question is has anyone changed the print head on a 9900 or 7900 that already had only B&W inks installed? Any issues?