How should the magnets be positioned in a Gibson P-90?
The same polarity of each magnet should be positioned towards the center metal spacer. If both magnet poles are facing the center metal spacer are South, then the adjustable pole piece will also be South. If both are North, then the adjustable pole will also be North. If they are both opposite facing the metal spacer then there will be little or no magnetic field in the adjustable polepiece to pick up the string vibration.
