Final drill nut plate mounting holes using #40 drill.
Final drill mount screw holes using #27 drill.
Debur and smooth all holes.
Machine c-sink light cup for flush rivets.
Rivet nut plates to light cup using p-squeezer.
Assemble light fixture.
Temporarily install in wingtip to verify clearance.
NOTE: I spoke with Dean at Aeroleds.com today about a replacement for the wingtip lights. he said that it was in the works and should be ready soon. About 75 LED watts and about $700 / pair. he is sending me the info...