You also need to turn the wiring "inside out" on one pickup - red and black become the coil tap point and green and white will be the hot and earth
This is what Feline said before... I am indeed not sure this step is needed: if the magnets are already flipped, so should the wires' "function", no?
If it was two single coils, you need RW/RP - reverse wind
and reverse polarity - for them to be a hum-cancelling pair.
Flipping the magnet only reverses the polarity.... so maybe you also need to flip the wires to reverse the wind of each humbucker coil?
But I'm really not sure!! I'd probably resort to trial and error. :lol: