Negative trigger is fine as you can hook up the power wire to the 12v and the ground to the negative trigger! I have 15" red neons in my door pockets so at night cars passing can see the door is open!
Hint: it is much easyer to tap the door triggers on a f-body! At the BCM! Passenger side uder dash blue plug at the BCM,BCM is located in the passenger kick,just in front of the blower motor! Use gray/black for drivers door and black/white as passenger door. Diode isolated or use a relay! As one trigger for both lights.