About how much to print to hit refilled cart ink?

About how much printing does it take for a 3880 to get through the ink in the lines and hit what’s in a refilled cart? I would rather not do a ‘fill’ cycle, the printer is printing beautifully and I just took out all carts to refill and replace the older K7 blacks with the HD blacks.

I have plenty of non-critical things and preliminary tests I can run, or some number of 8x10" 0-100% scales to be drawing on a cart and not the lines.

About 10x letter sized purge sheets using this method: How To Flush Individual Channel using QTR Calibration Mode

Or 3x power cleanings.