I couldn't see having the Inspection Door raised up on top of each rivit head. I end up pressing countersinks in the A4 Rivets holes. Also cut through the bottom skin to recess the A3 Nut Plate rivets. Took a bit of time but well worth it. Who knows, it might add another .01 mph to the cruise speed.
Bottom Skin ready for Riveting
Recessed Nut Plate Rivets
End result. The door is tight against the bottom skin